A flexible optical geometry of Fourier transform profilometry (FTP) is discussed. The fringe acquisition formula was derived, as well as the phase acquisition formula and the phase-height mapping formula, when the exit pupil of the projecting lens and the entrance pupil of the imaging lens do not share the same height and the axes of the two lenses are not in the same plane. Compared with the traditional Fourier transform profilometry, the experimental setup is simple and it is easier to obtain the full-field fringe through adjusting either the location of the projector or that of imaging device. Compared with the improved Fourier transform profilometry, only three length system parameters need to be measured, so the operation is simple and the measurement is more accurate.