To improve the fitting effect of frequency curve and to improve the calculation accuracy of design flood of large return period, application of LQ-moments (LQM) method in parameter estimation of flood frequency distribution is studied. Parameters of P-III distribution were estimated for six annual maximum flood series, and the estimation accuracy and fitting effect were evaluated and compared with LM methods and GEV distribution using δ、RMSE and MAE. The results show that LQM method results in satisfying fitting effect and P-III distribution is the best-fit distribution for three flood series and the LQM method is the optimal estimation method for five flood series. Compared with LM method, LQM method improves the estimation accuracy of design value of large return period, and is an effective method for the parameter estimation of flood frequency distribution.