Abstract: Aiming at the shortcomings of single-station traditional variance-weighted gross error detection cycle slip method, a Beidou cycle slip detection method based on single-station mutual error weighted epoch difference observation model is proposed. The carrier phase difference model between epochs is constructed from the observation data, and the mutual difference weighted adjustment method is used to perform gross error detection on the Beidou epoch difference data. Based on the chi-square distribution, the hypothesis and test are performed on the difference data to determine the satellite and the cycle slip value. The measured data shows that when effective satellites meet the positioning requirements, the method is sensitive to Beidou cycle slip, and it can accurately detect one cycle slip.