Aiming at the slow convergence rate of constant modulus algorithm,a soft-decision blind equalization algorithm was proposed on the basis of orthogonal wavelet transform.The blind equalizer structure of orthogonal wavelet transform and characteristics of soft-decision blind equalization algorithm are analyzed.Then the de-correlation ability of orthogonal wavelet transform is utilized to reduce the signal autocorrelation,thus accelerate the convergence rate of proposed soft-decision algorithm.Simulation tests with underwater acoustic channel indicate that the proposed soft decision-directed blind equalization algorithm is improved in convergence rate compared with parallel soft decision equalization algorithm.