In order to overcome the shortcomings of the ionospheric total electron content rate(TECR)and dual-frequency code phase combination(MW)methods, a combination of the two methods was used for cycle slip detection. First, the TECR method was used to detect the cycle slip. Then, the MW method was used to detect the cycle slip for the second time. Finally, the ionospheric TECR and the wide lane ambiguity of MW were used together to detect the cycle slip on L₁ and L₂ frequencies. This combined method was not affected by the geometrical distance between the receiver and satellite, the receiver clock offset, the satellite clock offset, and ionospheric refraction. According to the test results of measured data, the TECR and MW combined method is more effective and reliable than a single method in detecting GPS cycle slip.