In the detail structural steelwork, according to the problem of components in connection crashing at each other and the problem of the enough space of bolt installation, the paper expounds how to apply collision detection technology on steel structure designing software fast and effectively and then carries out reasonable test on component and node installation model. Based on bounding box and geometric data of objects in three-dimensional space obtained according to a certain rule, the paper deals with mutual relationship between spatial objects in the vector method and effectively solves the problem as well as finally programming collision detection model and bolt installation space test in the designing software of detail structural steelwork (STXT).