Abstract: Global Navigation Satellite System (GNSS) ambiguity fixed solution can greatly improve the accuracy of GNSS/inertial navigation system (INS) integrated system. But it is difficult to achieve perfect real-time dynamic single-frequency cycle-slip detection merely by GNSS observations especially in complex environment. Inertial aided cycle-slip detection term (DT) based on station-satellite double-differences and satellite single-difference observations are derived. The error characteristic of the DT is analyzed comprehensively. DT error is influenced by the error of INS positioning increment and this error of each satellite is related to the angle between its station-satellite vector and that vector of the base satellite. Thus, it is of importance to select base satellite. It is proposed that two group of DT can be used together by selecting two different base satellites. The threshold of detection is estimated in a moving window, where the DTs, whose INS error is submerged in GNSS error, are eliminated to reflect the effects of INS error. The threshold has strong self-adaptability.