The convergence of the Constant-modulus algorithm widely used in DVB system is a complex problem.Firstly,some influencing factors such as cost function,iterative equation and filter coefficients are considered;then,in this paper,an ameliorative algorithm with time-delay estimate is proposed,which can avoid converging to the ill solution by correcting the position of main path.Simulation results demonstrate the proposed algorithm can highly improve the convergence performance of the primary one.Besides,its simplicity and efficiency make it feasible in the high-rate 3G connection application.