The positioning of tunnel segments is the key to realize the automatic assembly of shield segments. This paper proposed a method for automatic assembly and positioning of shield segments based on the combination of deep learning vision and laser assistance. The plane pose and depth pose information of the segments to be assembled were obtained by vision system and laser ranging system, respectively. The vision system based on the specially designed two-stage convolutional neural network could effectively extract the contour features of the segment surface positioning marks, and the extraction accuracy and recognition rate were significantly improved compared with existing algorithms. Experiments show that the proposed automatic assembly positioning method of shield segment can meet the requirements of automatic assembly and positioning of shield segment.