In fringe projection three-dimensional measurement, double N-step phase-shifting profilometry compensates the phase error caused by the nonlinear response of the measurement system by expand twice the number of projection fringes, but the measurement efficiency is also reduced. To address the above concerns, an improved double N-step phase-shifting method is proposed in this paper. Compared with the traditional double N-step phase-shifting method, the proposed method can reduce the number of phase-shifting fringes while maintaining the measurement accuracy. The original and additional phase are calculated by using the deleted fringes, and the two phases are fused to realize the three-dimensional reconstruction of the object. Experimental results demonstrate that the proposed method has the same phase error compensation accuracy as the traditional double N-step phase-shifting method, and the measurement efficiency of the proposed method is improved by 16. 7%. At the same time, it is confirmed that the reliability of the three-frequency hierarchical phase unwrapping used in this paper is better than that of the three-frequency heterodyne method.