Objective:To analysis the support of Zhejiang and Shanghai laws on infectious disease prevention and control system,Clarify the role of legal guarantee level in the prevention and control system of infectious diseases,and to explore the method of quantitative evaluation on it.Methods:Systematic collection of all legal documents related to infectious disease prevention and control systems in Zhejiang and Shanghai,Cover the situation of the main departments (institutions) and its clear situation according to the legal liability clause,Comprehensive calculation of the supporting degree of the laws for infectious disease prevention and control systems,Spearman correlation and linear regression were used to analyze the relationship between supporting degree and incidence of infectious diseases.Results:In both Zhejiang and Shanghai, the degree of active improvement of laws and regulations related to infectious disease prevention and control system is gradually increasing, from 58.5% in 2000 to 76.8% in 2017 in Zhejiang,from 68% in 2000 to 71.6% in 2017 in Shanghai.There was a correlation between the support degree of the laws on infectious deseases prevention and control system and incidence of infectious diseases(the correlation coefficients were -0.609 and -0.890 respectively, both of which were statistically significant).Conclusion:The degree of support of the laws of Zhejiang and Shanghai on the infectious disease prevention and control system has improved and the effect is initially presented.Shanghai has better effect than zhejiang province,and both provinces have room for improvement.This study is scientifically feasible for the quantitative method of legal support.