The Gamma distortion is an important influencing factor of accuracy in fringe projection measurement. To improve the accuracy of measurement, an accurate and simple Gamma correction method is studied by analyzing the relationship between Gamma coefficient and harmonic coefficient. The accuracy and reliability of this method is verified through the simulation results. Finally, experimental work is done with this method. Compared with the retrieval phase without Gamma correction, the conclusion can be made that this method can effectively restrain the Gamma distortion of the system and improve the measurement precision.