The minimum mean square error (MMSE) detection method in the massive multiple input multiple output (MIMO) system has a problem that the matrix inversion complexity is too high. In recent years, there have been many studies to reduce the complexity. How to improve the convergence speed and detection performance of the algorithm while reducing the complexity of the detection algorithm has always been the focus of attention. The symmetric accelerated over-relaxation (SAOR) iterative algorithm is applied to the signal detection of massive MIMO systems, which avoids complicated matrix inversion calculation, and the implementation complexity is reduced by an order of magnitude compared with the MMSE method. The simulation results show that the SAOR-based detection method can approach the detection performance of the MMSE algorithm with fewer iterations, which provides a better implementation method for the fast detection of received signals in massive MIMO systems.