Massive Multiple Input Multiple Output（MIMO） systems have massive antennas at base station. The high dimension of the channel makes it difficult for mobile users to accurately estimate downlink channel in real time. To address this issue, a weighted Orthogonal Matching Pursuit（OMP） algorithm is proposed in this paper. Firstly, the estimated signal calculated by the algorithm in each iteration is divided into two parts, the signal estimated from current residual signal and the signal estimated from previous residual signal. Secondly, these two parts of the signal are set with different weights to improve the estimation accuracy under low Signal Noise Ratio（SNR）. Moreover, by adjusting the weight values with iterations, the estimation accuracy of the channel under both low and high SNR can be improved. The simulation results show that the proposed algorithm can obtain higher estimation accuracy than the standard OMP algorithm under different signal-to-noise ratios.

%U http://cea.ceaj.org/EN/10.3778/j.issn.1002-8331.1901-0204