Two different kinds of multi-span grape rain sheds are constructed and the wind field and rainfall field distribution are simulated based on CFD and computer simulation techniques. The airflow distribution, temperature variation, wind pressure distribution and rainfall vectors distribution are compared under two conditions with ventilated region and without ventilated area in multi-span grape rain shed. The research results show that set the ventilated area on the top of grape rain shed can improve effectively the high temperature and high humidity climate environment, and it has a benefit to grapes fertility.