A subspace-based blind channel estimation algorithm with cyclic prefix is proposed in this paper. A systematic approach is used to construct a new signal matrix in the proposed algorithm. Compared with conventional blind channel estimation algorithm, the proposed algorithm has lower computational complexity and higher probability of full row rank for the corresponding signal matrix. In addition, fewer OFDM symbols can be used to satisfy the necessary condition for achieving a full-row-rank signal matrix. Simulation results show that the proposed algorithm outperforms conventional methods in mean-squared error and bit error rate under static channel. Even with a smaller number of received OFDM symbols, the proposed algorithm can perform well.