With the need of 3D animation design for the 3D facial expression data dynamically, a 3D facial experession acquiring system was designed.Firstly, a new model was constructed by using a feature grating pattern and a space mapping method. Then，a feature grating pattern was designed, and the extraction method of a feature rectangle was provided.Furthermore, the relative phase was translated into an absolute phase by using the information of feature rectangle, and the three-dimensional world coordinate information was obtained by the space mapping method. Finally,the tests on accuracy verification and facial measurement were performed.A standard hemispheroid with (220±0.01) mm in diameter was measured five times，and the results show that the average of the fitting diameter is 219.95 mm, mean square error is 0.48 mm, and the mean square error of the distance between 3D points and spherical surface arrange is 0.28-0.46 mm. Moreover, the face with different expressions of a student was measured by the system,and the results indicate that the 3D data can be acquired by the system with only one fringe pattern and a vivid profile of the face is shown.