In order to achieve more efficient communication performances in vehicular ad hoc network (VANET) for road safety related message propagation, we propose a special nonbinary network coding scheme to improve the system reliability by reducing the outage probability of the communication system. Suppose all users in the network are provided with multiple antennas, which are responsible for message transmitting, relaying and receiving. Moreover, a cooperative phase is applied into the network. We analyze the exact expression of outage probability and give an approximation expression for calculating the outage probability over the Rayleigh fading channel. The simulation results indicate that the approximation expression has good performances on describing the exact expression.