Based on the wavelength tuning phase-shifting technology in Fizeau interferometer, a phase-shifting calibration method with step by step was presented. First, the n groups interferograms with t step were generatd , the step is π/2. Then, the error function for each step was built through the origin interferogram multiplied by n group of each step separately and making Fourier transform. Finally, the precision calibration was realized by calculating the extreme point of error function curve. The experiment results show that, the calibrating precision is better than the traditional ones and the calibration accuracy is up to 2 or 3 orders to compare with the traditional method. This new method not only avoids the random error, but also eliminates the accumulated error completely.