Gray coding method is widely used in 3D reconstruction of structured light projection because of its robustness and noise resistance. In order to apply gray code method to real-time measurement，multi-level Gray code is used to reduce the number of projection amplitude and improve the measurement efficiency. However，in the process of three-dimensional measurement with color objects，because of the difference in reflectance of different color，the fringe order in 3D reconstruction may be confused，and the error caused by chroma is obviosly increased by multiple gray levels. In order to adapt to real-time measurement for color objects and improve the characteristic of anti-color interference，a multi-level Gray code demodulation method using HSI color space is proposed. Intensity in HSI color space instead of the gray in RGB space is used in multi-level Gray code decoding and fringe order extraction，at the same time，the color texture of the object surface can also be reconstructed without capturing additional auxiliary color texture patterns. Experimental results show that this method can effectively correct the order entanglement caused by color object chroma，and reduce errors in fringe order. It may play a prospective application in real-time 3D measurement for color texture object.