Abstract: The application of partial filter in measuring ship deformation is studied. Nonlinear model of large angle deformation is deduced and the partial filtering algorithm is designed. Partial filtering simulations were made in small angle deformation and large angle deformation. Simulation results showed that the measurement precision based on partial filter is satisfaction in both situations and the partial filter is efficient in measuring ship deformation. The partial numbers which influence the filtering effect and the real-time question of partial filtering algorithm are discussed. The shortcoming of partial filter is also discussed.