Abstract: Ambiguity resolution is one of the key technologies for high precision GPS positioning. Accelerating ambiguity fixing can expand the application and improve the reliability of GPS positioning. Based on the characteristics of single-frequency GPS kinematic positioning, a new method to accelerate ambiguity fixing is proposed in this paper. First, a receiver and epoch double differenced approach was used to get the epoch-differenced coordinate information between neighbouring epochs. Then, the epoch-differenced coordinate information is combined with the ambiguity normal equation. Adding epoch-differenced coordinate information to the ambiguity normal equation can decrease the ill-posed-ness of the normal equation, so the accuracy of the floating ambiguity solution was improved and the convergence time of ambiguity was shortened. Experimental results show that the new method can accelerate ambiguity resolution in GPS relative kinematic positioning with good application value.