Abstract: By utilizing spring precipitation data of Yibin city in Sichuan province from 1953 to 2010, normal distribution, Gamma distribution, logarithmic normal distribution, P-Ⅲ distribution were applied to study the region's precipitation distribution characteristics. Based on this, the minimum of sum square variation method was used for goodness of fit test of the four distribution functions. The result shows that the four distribution functions can all fit with precipitation distribution of spring in Yibin city. The goodness of fit tests show that logarithmic normal distribution is best fit with the precipitation distribution of spring in Yibin city, Gamma distribution is the second best. The fitting effect of P-III distribution and normal distribution is relatively poor.

Key words: precipitation totals fitness, fitness test, comparative analysis