Abstract: To delete the measuring error of the optical phase shift resulting from the dithering of the interference fringes, a method is introduced. This method aims at the beam pointing instability induced fringe shift. The high frequency parts of the interference figures are get rid of, accordingly the quantity of the interference fringes dithering can be obtained. Based on this method, the phase shift of the soliton changing with the soliton power is obtained without the laser pointing instability error and the phase shift measurement of the nonlocal spatial solitons is realized.