Considering the blind signal separation problem of the convolutive mixture communication signals with same carrier frequency and modulation by a single channel,a new algorithm was presented for convolutive blind signal separation.Firstly,a single channel mixing signal model of MISO was transformed into a multi-channel mixing signal model of MIMO,based on the characteristics of oversampling.Then,the influence of the time-delay differences between mixing signal components to the structure and rank of mixing matrix of MIMO was studied.Finally,mathematical derivation proved that:if the time-delay difference between mixing signal components was the integral multiples of symbol velocity,the mixing signal is not blindly separable.And simulation results showed the validation of the algorithm.