Objective：To investigate the methods of predicting susceptibility of influenza A（H1N1） pneumonia at early clinical stage in outpatient department. Methods：Totally 206 patients diagnosed as novel influenza A（H1N1） in Chengde area between September and December of 2009 were concentrated in Chengde Hospital for Infectious Diseases for free treatment. The diagnosis was consistent with the Protocol for Diagnosis and Treatment of Influenza A（H1N1）（2009 3rd ed） issued by the General Office of Ministry of Health. A retrospective study on the 206 cases was conducted. Based on the final imaging findings，these patients were divided into pneumonia group（n=51） and non-pneumonia group（n=155）. Clinical characteristics and auxiliary examination were compared between the two groups；univariate analysis and multivariate logistic regression analysis were used to identify independent predictors of pneumonia；goodness of fit test was performed on an established clinical predicting scoring system. Results：Multivariate logistic regression analysis of the statistically significant factors demonstrated that：expectoration as initial symptom（OR=3.537，95%CI=1.016 to 12.311），onset-to-treatment interval > 48 h（OR=19.525，95%CI=4.576 to 83.309），lactic dehydrogenase > 250 U/L（OR=16.717，95%CI=5.484 to 34.417），potassium ion<3.5 mmol/L（OR=7.332，95%CI=1.763 to 49.709），aspartate aminotransferase > 40 U/L（OR=3.809，95%CI=1.008 to 12.460） and presence of underlying diseases（OR=61.003，95%CI=5.484 to 34.417） were the independent risk factors of influenza A（H1N1） pneumonia（all P<0.05）. Area under receiver operating characteristic curve was 0.965（95%CI=5.484 to 34.417，P<0.001）. Prediction scoring system of pneumonia was established according to levels of six high risk factors：low risk（score 0-2），intermediate risk（score 3-4），high risk（score 5-6） and very high risk（score 7） and were categorized for predicting the occurrence of pneumonia illness. Goodness of fit test showed good results（R2=0.916，P=0.043）. Conclusions：In the future，clinical physicians can predict the susceptibility of pneumonia in patients with influenza A（H1N1） by comprehensive scoring concerning initial symptom，onset-to-treat－ment interval time，level of serum potassium ion and aspartate aminotransferase and presence of underlying diseases.