Abstract: The paper aims to reduce the impact of continuous rain disasters on the growth and yield of the main food crops， Based on the farmland water balance principle，a continuous rain disasters index model was constructed on waterlogging duration，the level of drought-waterlogging and the degree of sunshine． It analyzes the occurrence law of Zhenjiang continuous rain disasters and the impact on the growth of the main food crops． The results showed that， the occurrence frequency of continuous rain disaster is 1 times every two years， the impact of 1~2 on wheat growth period，and the effect of 2~3 on Rice; it mainly occurred in wheat jointing stage，rice tillering and transplanting stage; Only 10% of the wheat and 8% of the rice in the years was not affected by the rain disaster; The relative meteorological yield fluctuation of 12~25% in wheat and 11~24% in rice was caused by continuous rain disaster． In order to scientifically prevent the influence of continuous rain disaster， a continuous rain disaster index model was built and the monitoring and early warning information was published to provide reference for prevention．