In view of the drawbacks of dominant parameter assessment in dealing with bad data in measurement，a method for robust parameter estimation using the weighted absolute least value（WLAV）based on dominant and non-dominant robust parameter estimation assessment is presented.The dominant assessment method is proposed by a systematic analysis of the causes of parameter estimation errors.Compared with the traditional linear interior point method，the model can be successfully solved by the nonlinear primal-dual interior point method（PDIPM），which is able to reduce the number of iterations greatly while improving the calculation accuracy.Finally，on the basis of the calculation and analysis of an IEEE 30-bus system and two actual provincial power grids，the performance of the proposed method is compared with the traditional weighted least square estimation，and the results show the effectiveness of the proposed method.