Abstract: The operation principle and configuration of electrical interfacebased freespace optical communication system are introduced in the paper. The antenna efficiency and collimated divergence angle of optical antenna are measured, antenna efficiency is about 35% and the collimated divergence angle is about 1.3mrad. The optical power of communication link is calculated. The result shows that the design meets the demand of 2km optical communication. The system consists of three parts: laser transmitting and receiving subsystems, optical antenna subsystem and media communication subsystem. Double transmitting and double receiving optical antenna is adopted to overcome atmospheric turbulence. The communication between computer and internet (or between computers) was implemented. The communication rate is 10Mbps/100Mbps and self adaptive, operational distance is 500m.