Abstract: The binary tree was widely used in the computer based interlock. According to the structure of the binary tree, this paper abstracted the signal points of the urban rail transit line into binary tree nodes, and constructed the binary tree model of the line, designed forward search algorithm and reverse search algorithm based on the preorder traversal of binary tree, implemented the search function which could realize interlocking function efficiently and protect the safety of the route. In this paper, the model of binary tree data structure was conducted in the central station of the sand table line 2 in the control laboratory of urban rail transit, and the VB software was adopted to complete the design of system's man-machine interface and main interlock function module.