Bit synchronization is one of the key technologies of space laser communication and measurement and control unified system. Its accuracy directly affects the performance of the whole system. Bit synchronous technique based on Gardner algorithm is easy to be interfered by self-noise of system. A self-noise abatement Gardner algorithm was proposed and a synchronous loop was presented based on this algorithm. Theoretical analysis and simulation results show that the self-noise abatement Gardner algorithm and the synchronous loop can effectively reduce the timing jitter caused by systems self-noise and have a faster bit synchronization establishing time when Eb/N0 is greater than or equal to 9 dB.