This paper has discussed the general condition and criticism standard about the study of hydrological frenquency curve types.Applied precipitation data of 78 series and optimum technique to analyse the fitting status of distribution curves of Log p-3 type, p-3 type, Gumber type and Log normal type with observed data. According to the principle of fitting goodness, we came to the conclusion that p₃ type distribution curve as a hydrological frenqency curve is reasonable.