Abstract: During maneuvering,performance of the Minimum variance distortionless response(MVDR) beamforming will greatly degrade due to the shape error of a towed array.Under the assumption that the shape of a towed array changes in a known way during the observation interval,an improved MVDR method is proposed.A static array with average shape during the observation interval is taken as a reference array shape.The phase difference of cross spectral density matrix(CSDM) between the time-varying array and the reference one is compensated on each azimuth.The CSDM accumulation can be achieved in the end.The simulation and experimental results show that the improved method has better performance than conventional MVDR with time-varying array,especially in solving the left-right target ambiguity and detecting weak signals.