Focusing on the sparse channel estimation of orthogonal frequency division multiplexing （OFDM） modulation system using greedy pursuit algorithms， the problem of recovery performance degradation caused by wrong selection of atom is studied. Based on the analysis of the least-squares reconstruction process in the greedy pursuit algorithm， it is found that there is a severe overestimation of the atom coefficients on the wrong atoms. On this basis， a coefficient optimization scheme （COS） using the channel path delay correlation between adjacent symbols is proposed to improve the accuracy of sparse channel estimation when the atom selection is wrong. The simulation results show that the combining COS with the traditional orthogonal matching pursuit （OMP） algorithm and sparsity adaptive matching pursuit （SAMP） algorithm can effectively suppress the effect of wrong selection of atom on sparse channel estimation， and increase the estimation performance of greedy pursuit algorithms under low signal-to-noise ratio. The simulation tests under different multipath channel models show great robustness.