Abstract: Vehicle rapid movement causes time varying channel, which will reduce the symbol error rate (SER) performance of intelligent vehicular cooperative system. Based on first-order autoregressive (AR1) model, a hybrid decode amplify forward (HDAF) cooperative strategy is presented, where the characteristics of time- varying channel are described by correlation coefficient of Doppler shift. The proposed strategy can select adaptively cooperative approach according to the variation of channel gain, and thus the controllable security of intelligent transportation system is enhanced. Moreover, vehicular velocities and estimation precision of channel state information (CSI) are analyzed. Numerical results show that the improvement of the CSI estimation precision will reduce the error-floor-value caused by vehicle rapid movement. Compared to amplify and forward (AF) and decode and forward (DF) strategies, the SER performance of the proposed strategy can be increased about 3.6 dB and 1.5 dB, respectively.