Based on LDPC-OFDM system, a multi-base station cooperative algorithm is designed for high frequency (HF) channel, and a LDPC cooperative decoding algorithm is proposed, which adopts information combining strategy based on the probability measure. The center station in the system model uses the multiple signals received from the relay stations to update its received initialization information. This strategy can combine the cooperative communication strategy with LDPC iterative decoding effectively in order to achieve both diversity gain and encoding gain. Simulation results show that the cooperative strategy with the multi-relay stations has better performance in the bit error rate than direct transmission strategy. The decoding performance of DF strategy with a relay station with respect to that of AF strategy has a gain of about 0.7dB at BER = 10-3.