Multistage Wiener filter (MSWF) is a very efficient algorithm for adaptive array processing because of low-complexity and prominent rank-reduction advantage. However, if training sample data was contaminated by outliers, especially when outliers having the same DOA with target emerge, the MSWF results will be decreased severely. In this paper, MSWFs backward iteration was improved, and median cascaded canceller (MCC) strategy was adopted so that optimal weighting calculation can be obtained via sorting and median processing, meaning impact of outliers were removed effectively. Blocking matrix solving of MSWF forward iteration was completed by Householder transform to enhance fix-point format performance. The new-designed algorithm attained excellent compromise between robustness and complexity. To verify presented algorithm's performance, array with 50 elements was established in simulation platform, and the simulated results also proved it can cope with outlier-contaminated applications effectively.