Abstract: A novel blind channel estimator based on computing Roots of Matrices (RM) is proposed for OFDM systems. This algorithm exploits the finite alphabet property of information symbols and implements channel deconvolution by computing the Jth principle root of a low-triangular Toeplitz matrix. Therefore, RM algorithm has much lower computation complexity than searching algorithms in previous works and is able to function in the case of large channel order that is intractable by searching algorithms. Moreover, an Adaptive RM (ARM) algorithm is proposed to adjust RM estimator by steepest descent method. Simulation results indicate that RM algorithm has great accuracy comparable to the optimal exhaustive search and ARM improves the estimation performance of RM considerably.