Because the intersatellite optical communication system is unable to perform optical relay amplification, optical receivers with high bit rate and high communication sensitivity are desirable. In this study, we first theoretically analyze a high-sensitivity homodyne coherent receiver when an erbium-doped optical fiber amplifier (EDFA) is used as the optical preamplifier. A homodyne coherent receiver based on EDFA is developed, and the performance of BPSK communication system is experimentally analyzed at a communication rate of 8-10 Gbit/s. Experimental results show that the coherent receiver achieves a sensitivity of -48 dBm when the uncoded BER is 10 ^-3 for the 10 Gbit/s BPSK signal. The receiver performance shows only 7 dB penalty compared with quantum noise limit; this value is better than the published test results for the 10 Gbit/s homodyne coherent communication system.