Abstract: This paper studied on blind equalization algorithm based on Decision Feedback Equalizer and applied the idea of combining CMA with DD-LMS to update the coefficient of blind decision feedback equalizer based on a modified constant modulus cost-function in which a leaking gene was brought,then an variable step size algorithm combing DD-LLMS with MCMBDFE was derived which has an extensive applicability and a goodish equalization property.This algorithm which has a fast convergence rate and a lower residual error when converged recovers the channel phase error automatically while equalizing,it also solves the problem of coefficient excursion which was produced by LMS algorithm when the equalizer has no continuous input.Computer simulation validates that the algorithm of blind decision feedback equalization combing DD-LLMS with MCMBDFE is effective.