Abstract: The fixed algorithm with high efficiency and success rate for integer solution of ambiguity is a key technology for achieving rapid and even real-time precise positioning using GNSS, and Ratio value test is one of the technical indicators for determining the reliability of the optimal integer solution of ambiguity. In order to enhance the reliability and success rate of ambiguity resolution, here proposes a new strategy to improve the success rate of ambiguity resolution based on the selection weight fitting method. The strategy involves selecting the optimal selection weight fitting factor value to obtain a higher Ratio value, and selecting the integer solution corresponding to the maximum Ratio value as the most reliable solution. Theoretical analysis and experimental results show, although this method may affect computational efficiency, it can significantly improve the reliability and success rate of integer ambiguity resolution, achieving a success rate of over 99.96% for single epoch ambiguity resolution of short baseline, and promoting the extended application of the precise dynamic real-time positioning technology.