为了在非线性测量系统中获得更好的相位测量结果，提出了一种在几乎消除非线性影响后使用双频光栅投影的相位测量方法。首先，讨论了相位测量系统的非线性效应，分析了频域中存在高阶频谱成份的基本原因，给出了减小非线性效应并分离基频信息的基本方法。然后，在减小系统非线性效应影响的基础上，分析了使用双频光栅投影测量被测物体条纹图像的相位基本原理。为验证所提出的相位测量方法的有效性，进行了计算机仿真和实际实验，获得了良好结果。在仿真实验中，该方法的误差值为有非线性影响方法的27.97%，为几乎没有非线性影响方法的52.51%；在实际实验中，该方法的相位恢复效果最好。表明采用本文方法所测量的相位效果好，误差较小。

To gain better phase measurement results in nonlinear measurement systems, a phase measurement method that uses dual-frequency grating after reducing the nonlinear effect is proposed. Firstly, the nonlinear effect of the phase measurement system is discussed, the basic reason for the existence of high-order spectra components in the frequency domain is analyzed, and the basic method used to reduce the nonlinear effect and separate fundamental frequency information is given. Then, on the basis of reducing the nonlinear effect’s influence on the system, the basic principle of phase measurement for the fringe image of a measured object using the dual-frequency grating method is analyzed. To verify the correctness and effectiveness of the proposed phase measurement method, a computer simulation and a practical experiments were implemented with good results. In the simulation, the error value of this method was 27.97% for the method with nonlinear influence, and 52.51% for that with almost no nonlinear influence. In the experiment, the effect of phase recovery produces the best results. This shows that the proposed phase measurement method is effective with a small error.