Abstract: Cycle-slip detection and correction is an important issue in high precision kinematic GPS positioning, which seriously affects the efficiency of solving ambiguity on-the-fly. A new algorithm avoiding the shortcomings of triple-differenced methods to detect and repair cycle-slip based on double differenced model between receivers and epochs is proposed. First, outlier detection is used to locate the possible cycle-slip affected double difference, carrier phase observations, and the initial cycle-slip value can be determined. Finally, a cycle-slip optional combination search approach, based on the principle of least sum of squared residuals, was adopted to repair the cycle-slip. Theoretical analysis and experimental results show that cycle-slips can be located and repaired accurately with this new algorithm in most cases, when the number of effective observed satellites was not less than four.