Objective：To study the influencing factors of specific disease in the maternity insurance and to give the evidence for payment system according to specific disease. Methods：Structural equation models were used to analyze the data of 1525 cases from 4 hospitals in Nanjing from 2002 to 2004. Results：The effect coefficient of the clinical characters, the quality of medical care and the social-economic character was 0.9334, 0.3194, 0.2230, respectively. In the 3 latent variables, the effect coefficient of clinical characters was the most significant on the medical cost. Conclusion：Ｓtructural equation models could be established and effectively analyze the influencing factors of specific disease.