In a cooperative communication system, inter-carrier interference (ICI) appears due to the Doppler shift, which severely degrades the performance of the OFDM scheme. In this paper, we concerned with signal decoding in cooperative space frequency block coding (SFBC) based OFDM system, while combating ICI at the same time. Specifically, the decoding algorithm is proposed by using the received signal on odd-numbered and the even-numbered subcarrier to decode data in pairs in the scenario of high-speed mobility.