The traditional multi-surface wavelength tuning phase-shifting interferometry can only achieve the measurement of transparent objects in fixed positions, and the effectiveness and solution accuracy of the algorithms are not intensively discussed and analyzed when the phase-shifting value or cavity length is changed. To achieve the simultaneous measurement of various surfaces of the transparent objects at arbitrary cavity lengths, a weighted multi-step sampling algorithm that can achieve adaptive phase shift matching is proposed in this paper. Firstly, based on the characteristic polynomial, a weighted multi-step phase demodulation technique with phase-shifting error and coupling error suppression capability is introduced, which can measure three surfaces of a transparent object simultaneously. Then, based on the Zernike polynomial, the algorithm solution error is iteratively calculated and analyzed for the arbitrary combinations of the phase-shifting reference coefficient and cavity length coefficient to provide a reference for the optimal parameter matching. The simulation results show that the residual error of the proposed algorithm solution is less than 3×10 -4 λ0 . Besides, the 3D height parameters in the ISO-25178 series are introduced to verify the algorithm performance. In the experiments, a Fizeau interferometer was used to measure the transparent flat plates with thicknesses of 10 and 5 mm, respectively at different cavity lengths. The simulation and experiment results show that the proposed algorithm can achieve multi-surface measurements at arbitrary cavity lengths and thicknesses, and its reliability and practicality are verified.