Abstract: In Precise Point Positioning, the integer ambiguity does not have integer property, how to solve it accurately has always been a hot topic in recent research. Moreover, in the initial stage,a long time observation should be taken to make the positioning result converge to centimeter to decimeter level. In order to solve this two problems, the shorttime high accuracy positioning information output from the inertial navigation system can be introduced in ambiguity resolution, making the calculation faster and more accurately. The paper describes two kinds of least square methods, including using INS position information to substitute directly and building the virtual observation. Then, the relationship between INS accuracy and accuracy of ambiguity resolution are also discussed under two methods. The simulation result shows that the INS position aiding can effectively improve the efficiency and accuracy of ambiguity resolution, shorten the convergence time and improve the positioning accuracy.