Modeling groundwater vulnerability to pollution is critical for implementing programs to protect groundwater quality. Most groundwater vulnerability modeling was based on the current hydrogeology, however, climate change will also affect the vulnerability in karst area. In this research, writers chose the COPK model, which was added the recharge model PI as a model development to assess the groundwater vulnerability and the effect of the rainfall from 2008 to 2012 on vulnerability assessment. The vulnerability assessment was verified using the concentration of CI~-, NO_3~- and SO_4~- in Jiangjia Spring. It showed that the high vulnerable areas are in sinkhole with their surrounding 100 m area. The rainfall in basin has an obvious effect on the vulnerability, with the rainfall and extreme rainfall times increasing,the high vulnerable area enlarge at the same time.