Due to low signal-to-carrier ratio and high dynamic, the frequency deviation affects the bit synchronization in GNSS receiver. This paper proposes a balance differential coherent bit synchronization algorithm, which uses the differential coherent method to eliminate the influence of the frequency deviation. By enlarging the differential distance, the proposed algorithm achieves higher bit synchronization rates. Combining two complementary differential coherent parts, the proposed algorithm avoids the unbalance problem and the attenuation of accumulation. Furthermore, a general architecture is presented to reduce the system complexity. Experimental results show that the proposed algorithm improves the sensitivity of bit synchronization by 3∼7dB compared with the previous method.