In this paper, the method of crop growth simulation is introduced into disaster risk assessment and combined with statistical method. Based on the theory of natural disaster risk assessment, the drought evaluation index and comprehensive risk assessment model of summer maize in Henan Province were constructed by using the historical weather data, the observation data of summer maize and the related social statistical data of agricultural production. The results showed that the biggest drought risk stage of summer maize growth season in Henan province was mainly the sowing to emergence stage and milky to maturity stage. In terms of spatial distribution, the northern and western regions are the most dangerous, which is mainly affected by the uneven distribution of precipitation in time and space. Therefore, strengthening the construction of irrigation and water conservancy facilities and improving irrigation conditions in major agricultural producing areas are the most effective ways to reduce drought risks and ensure stable agricultural yields.