Abstract: Aim to the problem that the signal noise ratio (SNR) of each user is assumed to nearly the same, so that the cooperative performance can not be improved remarkable in the larger difference of SNR environments, based on SNR information, a novel cooperative spectrum sensing scheme for OFDM system is proposed. By using the characteristics of cyclic prefix of OFDM signal, the novel blind SNR estimation is proposed without any information of modulation or synchronization for the cognitive radio system. Moreover, by using the characteristics of detection probability curve which is close to the linear between -13dB and -5dB, and according to the estimated SNR, the detection probability curve can be quantized into the soft-information as decision believe degree information in order to attain more reasonable weight in fusion scheme. Computer simulation shows that the proposed scheme can utilize the SNR information effectively. And comparing with the conventional scheme, the performance of proposed scheme is better in various situations. Especially in the larger difference of SNR environments, the performance of proposed scheme is closer to data decision scheme.