【Objective】 To review published literature and perform a meta-analysis summarizing the evidence in support of the association between childhood asthma and three exposure factors (indoor air pollution by using coal for heating, respiratory infections and breastfeeding). 【Methods】 Online database were systematically searched which included China Journals Full-text Database for publications since 2002. The meta-analysis included only original studies. It was used to derive a combined odds ratio(OR) and 95% confidence interval(CI) and test for heterogeneity in the findings between studies. 【Results】 5 studies met inclusion criteria. Compared with control, respiratory infections conferred the most significant increased odds of childhood asthma(OR:2.26,95%CI:1.88~2.64). Similar increase in the OR of childhood asthma due to indoor air pollution(OR:0.35,95%CI:0.20~0.50) was also observed. Breastfeeding was the protective factor of childhood asthma(OR:0.36,95%CI:0.55~0.17). There was no evidence of heterogeneity that was statistically significant(P<0.05). 【Conclusions】 This analysis found strong and consistent association between respiratory infections and childhood asthma in China. It suggests that there is minor effect of indoor air pollution on childhood asthma. And breastfeeding was found to be protective factor. More works need to be done to improve breastfeeding rate because the rate shows a tendency to descend as a result of the fast rhythm of urbanism in China.