A novel model of three-dimensional (3D) shape measurement in fringe projection profilometry (FPP) system is proposed, which doesn′t need to meet the constraints of the link of the two optical centers being parallel to the reference plane, the axis of imaging system being perpendicular to the reference plane and the two axes intersecting on the reference plane. This new model just requires the sinusoidal fringes projected on the reference plane are parallel to each other, so it is easy to implement the adjustment of the FPP system. The undetermined coefficients of the achieved phase-to-height relationship are irrelevant to the coordinates of imaging points. The coefficients can be obtained by means of least square method by sampling a number of points, not every one, so the calibration time is reduced a lot. The experiments demonstrate that the adjustment of the FPP system is simple, so the speed of the system calibration is improved greatly. Moreover, the accuracy of this new 3D measurement system is high, and it can measure the objects with complex surface shapes. Therefore, the novel method enhances the practicability of FPP system.