In order to improve the accuracy of projected fringe deflectometry (PFD) in measuring the free-form surface, a standard intensity insensitive five-step phase-shifting algorithm in PFD test is proposed by analyzing the change patterns of the intensity on the tested surface. Fourier techniques are used to analyze the feasibility of the algorithm. The result of the computer simulation indicates that the peak value of phase retrieve precision of the proposed algorithm is 0.0042λ and the root mean square value is 0.0014λ with 1%~5% change in standard intensity and 0.1%~0.5% stray noise. After removing defocus, the precision of phase retrieve is 0.0009λ. By comparing with other phase-shifting algorithms, the performance of the algorithm manifests the advantages. As a result, the standard intensity insensitive five-step phase-shifting algorithm has a high application value in the measurement of free-form surface in PFD.