Coded structured light based on 3D detection is an active-vision method, which projects certain coding pattern through the projector, and obtains the matching points and depth information through triangle principle. For realizing fast measurement of surface, a pseudo-random array encoded method is used. Because the M-array generated by diagonal line is unable to meet the requirement of size for projecting desire pattern, an algorithm which may generate M-array of the large suitable size is studied. It lays the foundation for improving the measurement of spatial resolution and measuring precision. Over the field of three elements, monochromatic light is used, and we choose the stripe, circle and disc as M-array symbols. The symbols are easy to be identified and distinguished, provide information for decoding image search and increase the anti-interference ability for the environment. The pattern is robust as it allows a high error rate characterized by Hamming distance higher than 3. Results of reconstruction verify feasibility and effectiveness of presented method.