Empirical Studies Of China's Grain Comprehensive Insurance Rate

China is a country which has many natural disasters. Natural disasters has become a major cause of restraining food production in China, its food security could be greatly affected. Insurance is able to disperse risk,therefore agricultural insurance is One of the effective measure to resist natural calamities of agriculture. Central governments and local governments attach great importance to agricultural insurance, hoping to develop agricultural insurance, perfecting the agricultural insurance system, and strengthening management and control in the risk of agricultural production, reduce the impact of natural disasters on agriculture and increase the income of farmers.This paper gets down to the partition the risk of natural disasters in food production and food security net rate, through the provincial risk, make reasonable zoning and set rational net premium. It is hoped that this research way could be applied on other types of agricultural insurance to promote the development of agricultural insurance. This article is divided into two parts. The first part, through comparing all kinds of the principles of seting the index and improving the coefficient of variation, the planting area as weight will be introduced as its computation formula, thus establish five index , the amendment coefficient of variation, the probability of yield decline, specialization index, the relative yield level, the probability of disaster, use hierarchical clustering and K-means method, divide the production risk in national food disaster, into province unit, as the results showed that, critical natural disasters in China mainly concentrated in the north of Yangtze River, and particularly more serious in the Midwest, natural risk is also high in major grain producing areas. The second part, improve the relative ratio method. it is more reasonable to introduce planting area into the calculating formula of relative ratio based on the risks zoning in agricultural production, through the improved ratio method, calculate the 31 provinces of pure grain insurance rates. By risk-risk area and the analysis of conclusions in grain pure rates, some suggestions have provided to promote the development of China's agricultural insurance.