Traditional Gray-code assisted four-step phase shifting phase unwrapping method requires projection of four stripe patterns ,but the reconstruction accuracy is not high due to factors such as environmental noise and defocus- ing of the projector. In order to improve the efficiency and accuracy of three-dimensional reconstruction ,a phase un- wrapping method combining Hilbert transform and Gray code is proposed. First ,the cosine component is obtained u- sing the acquired sine stripes image and the background light intensity image ,and then the cosine component is con- volved with the shock response using the Hilbert transform. Shifting the phase by π/2 while keeping the original fre- quency and amplitude unchanged. Finally ,the absolute phase of the measured object is solved by using the phase or- der obtained by Gray code decoding. In addition ,the tripartite phase unwrapping method (Tri-PU) is used to elimi- nate the edge hopping error in the process of Gray code phase unwrapping. The experimental results show that the ac- curacy of the proposed method is 0. 045 mm in the reconstruction of high precision standard ball ,and the reconstruc- tion accuracy is high. The projection stripe images are reduced from four to two ,which improves the projection effi- ciency.