Objective To construct an external quality control evaluation system for epidemiological investigation of major infectious diseases. Methods By consulting relevant policies and literature

according to the actual situation of prevention and control in major infectious diseases demonstration areas

combined with the Standard Operating Procedures for Large-scale Field Epidemiology and Intervention of Major Infectious Diseases such as AIDS

Viral Hepatitis and Tuberculosis

the external quality control evaluation system for epidemiological investigation of major infectious diseases was preliminarily constructed. A total of 23 experts were invited to evaluate and screen the content of the index system by Delphi method. Results In this study

the effective questionnaire recovery rate of the first round consultation was 100.0%. The effective questionnaire recovery rate of the second round consultation was 91.3%. The authority coefficient of expert opinion of the first-level indicator was 0.798 in the first round of consultation; and 0.791 in the second round of consultation. The coordination coefficient of all indicators in the first round of expert consultation was 0.406（P<0.05） and that of all indicators in the second round of expert consultation was 0.325（P<0.05）. The final index system consists of 4 first-level indicators

13 second-level indicators and 54 third-level indicators. Conclusion The establishment of the index evaluation system enables quality control inspectors to follow the criteria for multicenter quality control work

and can evaluate the investigation process and results more objectively and fairly.