The invention discloses a weak signal processing method based on a GNSS receiver. The method comprises that a satellite navigation signal is captured; the satellite navigation signal is tracked via a frequency-locked tracking loop; after stable tracking of the frequency-locked tracking loop, the accumulative amount of the satellite navigation signal is cached via first incomplete coherent accumulation bit synchronization, and the bit hopping edge calculation value of the satellite navigation signal is calculated; the satellite navigation signal enters a phased-locked tracking loop via the frequency-locked tracking loop; and after stable tracking of the phase-locked tracking loop, the bit hopping edge verification value of the satellite navigation signal is calculated via second incomplete coherent accumulation bit synchronization, and loop tracking is determined to succeed when the bit hopping edge verification value is consistent with the bit hopping edge calculation value. According to the invention, the weak navigation signal can be effectively tracked, and the problem of bit edge overturn in a long coherent integration time slice is effectively overcome.