The low rural sewage treatment rate is mainly due to the shortage of sewage collection systems, purification facilities and operating funds. Based on the data of the existing projects and combined with the distribution of rural population in Taihu River Basin of Jiangsu Province, the fund demand for sewage treatment facilities and the annual operating and regulatory costs after the completion of all the facilities are preliminarily estimated when the rural sewage treatment rate reaches 70%. The solutions to the fund gap are analyzed, and some policy recommendations for financial security are also proposed.