To overcome the atmospheric attenuation effect, the non-line-of-sight scattering atmospheric optical communication system usually adopt an optical antenna to enhance the signal collection ability and increase its communication distance. Some conventional optical antennas like hemispherical lens, compound parabolic concentrator (CPC), Cassegrain telescope were analyzed with the software of ZEMAX. The results show that the field of view (FOV) of hemispherical lens and CPC are wider and its gain is higher compared with other optical antennas. The variation of the photons′ energy intensity distribution with the communication distance was calculated with Monte Carlo method, with CPC and hemispherical lens as the optical antennas. The result shows that the light collection capacity of CPC optical antenna is better than hemispherical lens optical antenna, and CPC is the more suitable optical antenna for non-line-of-sight scattering atmospheric optical communication.