A new method of voltage sag state estimation based on the singular value decomposition is presented in this paper. Compared with ANN and GA algorithm and so on, there is no convergence problem because of without iteration, and it has the advantage of less estimated time.Then based on the DIgSILENT software for distributed power access distribution network voltage sag state estimation for simulation analysis. Combining multiple case simulation analysis of two different types of DG is synchronous machine and inverter models and their different control strategies and DG output will produce certain influence to voltage sag state estimation, the results show that different distributed power access grid solutions will lead to different extent difference on the entire network voltage sag problems.