The Infectious Diseases Department is one of the earliest-established departments. It was initially set up as the Department of Communicable Diseases when the hospital was founded in 1962 and was renamed the Department of Infectious Diseases in 2003. Originally, it had 17 beds. In 1980, it was relocated from Yuechuan to No. 1154, Jiefang Road, Sanya City. Three rows of one-story bungalows with a mixed-structure were built, with a total of 28 bungalows and 56 beds. It was divided into an intestinal infectious disease ward for treating hepatitis, dysentery, etc., an insect-borne infectious disease ward for treating malaria, dengue fever, etc., and a respiratory infectious disease ward for treating tuberculosis, etc. The environment was beautiful with good air quality. Patients can move freely in the yard, which reduces their psychological stress. It is conducive to their physical recovery. A new building for the Infectious Diseases Department was constructed in 2004 and put into use in 2005. It integrates wards and outpatient services. It is currently the largest and most professionally-staffed infectious disease specialty in southern Hainan, undertaking the diagnosis and treatment of infectious diseases in southern Hainan. Especially during the COVID-19 outbreak in 2020, it made indelible contributions to prevention and control. Due to new prevention and control requirements, the inpatient department of the Infectious Diseases Department was relocated to Sanya Public Health Clinical Center (Jiyang Avenue, Jiyang District, Sanya City) in July 2023, and it continues to function as the center for the prevention and treatment of infectious diseases in southern Hainan. It officially opened to receive infectious disease patients in April 2024. However, the intestinal outpatient, liver disease outpatient, respiratory and fever specialty outpatient are still retained in Sanya Central Hospital, basically meeting the public's needs for consultation, health care, diagnosis, and outpatient treatment of infectious diseases.

Currently, there are 9 medical staff in the Infectious Diseases Department, including 1 chief physician, 1 associate chief physician, 4 attending physicians, 2 resident doctors, and 1 associate chief nurse. The Department of Infectious Diseases mainly admits various severe tuberculosis cases, viral hepatitis, decompensated liver cirrhosis, AIDS, AIDS with opportunistic infections, fever of unknown origin, and other infectious diseases (such as septicemia, septic shock, severe hand-foot-and-mouth disease, chickenpox, measles, dengue fever, mumps, epidemic hemorrhagic fever, malaria, tsutsugamushi disease, rickettsiosis, scarlet fever, typhoid fever, leptospirosis, bacillary dysentery, etc.). Meanwhile, it is responsible for the antiviral treatment and management of AIDS patients in the Sanya area. It has rich experience, especially in severe hepatitis, refractory tuberculosis, and diseases with fever of unknown origin. In recent years, the antiviral treatment of chronic hepatitis B and C has effectively prevented the continuous damage of the virus to the liver, significantly reduced the incidence of liver cirrhosis and liver cancer after chronic hepatitis B and C, and improved the quality of life of patients. It has extensive connections and cooperation with the Hainan Provincial Infectious Diseases Hospital for a long time and conducts online video consultations with many domestic infectious disease hospitals to solve complicated cases. The department admits a complete range of infectious disease types with a wide source of patients. Its medical services are based in Sanya and radiate throughout the province. The department promotes clinical diagnosis, treatment, and research on newly-emerging and re-emerging infectious diseases, making significant contributions to the public health cause in Hainan Province. Especially in 1996, it participated in the cooperation with Guangzhou University of Chinese Medicine in the research on the treatment of malaria with artemisinin, achieving good results. It made indelible contributions to the elimination of malaria in Hainan Province and the global promotion of artemisinin. During the fight against Severe Acute Respiratory Syndrome (SARS) in 2003 and subsequent infectious diseases such as hand-foot-and-mouth disease and influenza A (H1N1), the Infectious Diseases Department undertook important diagnosis and treatment work in southern Hainan, receiving good evaluations and praise from the Hainan Provincial Health Department and the Sanya Municipal Health Bureau. Since the outbreak of COVID-19 in 2020, its role in southern Hainan has become more prominent, making significant contributions to the phased victory of Sanya in the fight against COVID-19. The Infectious Diseases Department won the title of "National March 8th Red-Flag Collective" and the title of "Hainan Province Women's Civilization Post" in 2020. The overall medical skills of the medical staff in the department are excellent, and the service quality is good, making the ward as warm as home.