In order to study the outage probability of spatial coherent optical communication system under the combined effect of atmospheric turbulence scintillation effect and pointing error, a coherent optical communication system model based on balanced detection is established based on the exponentiated Weibull atmospheric turbulence fading channel. A probability density function of channel attenuation of the system under the combined effect of atmospheric turbulence scintillation effect and pointing error is given, and closed expressions of the system outage probability are derived. The effects of turbulence intensity, beam width and jitter deviation on the system outage probability are analyzed through the numerical simulation. The results show that the system outage probability increases with the increasing of the turbulence intensity and the decreasing of the normalized signal-to-noise ratio. The system outage probability can be decreased through increasing the beam width when the normalized signal-to-noise ratio is greater than 14 dB. In addition, the increase of the normalized signal-to-noise ratio cannot effectively reduce the outage probability of the system when the jitter deviation is greater than 2. Based on the simulation results of the proposed model, it is concluded that the appropriate beam width and jitter deviation can reduce the outage probability and improve the stability of the system.