In this paper, a new channel estimation method for OFDM WLAN systems is proposed. This proposal mainly consists of smoothing filtering and decision-directed tracking loop schemes, where the former is used to enhance performance at low SNR and the latter is exploited to enhance performance at high SNR respectively. Together with an adaptive channel management, bener performance in terms of MSE and PER can be achieved. Simulation shows the proposed method ( I ) achieves better 9.0dB - 13.0dB gain in MSE than zero forcing criterion and bener 2.0dB gain in MSE than conventional approaches in BPSK transmission, and (2) contributes 0.8dB. 2.0dB gain in SNR for 10%PER in different transmission modes.