This paper presents a robust method for power system state estimation along with a statistical technique of data debugging. In the estimation process, an exponential function is utilized to modify the variances of measurements in anticipation of enhancing the estimation performance and improving the convergence characteristics. Besides, with the aid of Monte Carlo method (MCM)-based clustering analysis, those bad data can be effectively identified from the set of raw measurements. To validate the effectiveness of the proposed approach, this method has been tested under different scenarios. Test results help confirm the feasibility of the method for the applications considered.