Abstract: Objective To investigate influencing factors of epidemiological investigation ability among emergency responders of centers for disease control and prevention(CDCs).Methods With random cluster sampling,1 033 emergency responders in ten cities of Heilongjiang province were investigated with a questionnaire survey and qualitative interviews.Descriptive statistics,analysis of variance,logistic regression were adopted in data analyses.Results The overall score of on-site evaluation of epidemiological investigation ability was 3.18?0.732.Four influencing factors were identified,including whether or not being responsible for the field epidemic investigation(odds ratio=2.615),personal protection ability(OR=1.490),training efficiency(OR=2.293),and proficiency in emergency exercise(OR=4.670).The factors influencing field investegation were lack of funding,shortage of professional staff,and lack of technical instruction.Conclusion The epidemiological investigation ability of emergency responders from CDCs is low and the ability should be improved by enhancing personal protection and conducting appropriate training and exercise.