Objective:To provide scientific and effective theory for the healthy development of medical waste disposal management in medical institutions at all levels in Nanjing, based on the investigation and analysis of the situation of medical waste disposal in primary medical institutions in Nanjing from 2016 to 2018.Method:The objects of the survey are 36 primary medical institutions located in 6 districts of Nanjing that participated in the pilot project on classified supervision and comprehensive evaluation of infectious disease prevention in medical institutions from 2016 to 2018. In accordance with the law of the People"s Republic of China on the prevention and treatment of infectious diseases, the regulations on the management of medical waste, and the measures for the management of medical waste in medical and health institutions, the rating form for the medical waste disposal in medical institutions is created. According to the investigation and the importance of the 12 survey items in the rating form, the scores for all items are assigned. The actual score of each primary medical institution in each year is computed and then converted into the standard score (standard score = actual score/full score×15) that is used for statistical analysis. The change trend of standard scores of medical waste disposal in the six districts of Nanjing is studied, and the statistical differences between different years and between different districts are compared.Results:1. From 2016 to 2018, the average standard score and standard deviation of medical waste disposal in primary medical institutions in six districts of Nanjing are 13.32 points and 2.18 respectively. 2. Overall, the differences from 2016 to 2017 and from 2017 to 2018 in the standard scores of medical waste disposal in primary medical institutions in six districts in Nanjing are statistically significant (P<0.05). 3. The difference in the three-year standard scores between the Gaochun district and any other district is statistically significant (P<0.05).4. From 2016 to 2018, the fifth of the 12 survey items on the disposal of medical waste in primary medical institutions has the highest increase of standard score. By 2018, except the 12th survey item with score of 25 points (out of 36 points), the remaining items have received full scores. Conclusion:1. From 2016 to 2018, the capacity of medical waste disposal in primary medical institutions in Nanjing has been improved significantly year by year.While the Gaochun district always did the best in the medical waste disposal.2. From 2016 to 2018, the fifth survey item "using special packaging and containers" in the medical waste disposal has been improved the most, and the 12th survey item "disinfection treatment and monitoring of hospital sewage" still needs to be strengthened in the later work.