Abstract: The channel estimation method that based on the PN sequence is generally characterized by a concise computational process and a lower computational complexity,which has been already applied in the terrestrial WLAN system.While adopting such means for estimating SOFDM symbols in satellite communication,there comes a problem that the multipath delay is much longer than the period of SOFDM symbol,which makes the traditional measure failed and the estimate precision lost.Therefore,an improved method was proposed,which divided the data frame into several fixed groups by considering that the channel characteristics was approximately cycled with a periodicity which was related to the RMS value of multipath delay.Afterwards,the long PN sequence was designed to be truncated to many short PN codes in order to track the partial changes of the channel,thus their channel response value(CRV) could be estimated respectively.The experimental results prove that it is able to estimate data symbols' CRVs with a higher accuracy and improve the estimate precision by at least 10 times paralleling to that of other ordinary methods.