Objective To analyze the risk factors of hospitalized children with acute asthma exacerbation in Chongqing region. Methods A total of 193 cases were randomly selected from the hospitalized children with acute asthma exacerbation in Chongqing Children’s hospital and Jiangjin District People’s Hospital from January 2009 to December 2009. A self-designed questionnaire was used to collect data. A control group of children were randomly selected from the out-patients who received regular maintain therapy without asthma attacks for more than 3 months. Results The first independent risk factor of asthma hospitalization was respiratory infection ( 85. 5%, 165 /193) . Irregular use of control medications was the second important factor for the acute exacerbation. There were 75% ( 138 /193) patients didn’t take controlmedications regularly, includes 102 undiagnosed and 36 pre-diagnosed cases which was more common than that in regular maintain therapy group ( 21/110, 19. 1% ) . A variety of allergen-induced acute exacerbation of asthma was also common, which accountted for 9. 3 % ( 18/193) . There were more boys than girls ( M/F:124 /69) and no significant difference in the family history of allergic diseases ( P gt; 0. 05) . Conclusion Respiratory infection, under-diagnosis of asthma, and irregular use of the control medications are risk factors of acute exacerbation in children with asthma in Chongqing region. Meanwhile allergen exposure warrantsmore attention.