Along with the development of simulation technology, systems of three-dimensional simulation are being used in more and more domains. The distance of objects is one of the important measures which are used to estimate the relationship of object’s position and to weigh the attributes of their own movement. The distance computing places an important role in the system of 3D simulation. In this paper, the two-phases (broad-phase and narrow-phase) algorithm for computing distance is presented. Using the algorithm, finally we have got the minimum distance of objects, and the feasibility and veracity of the algorithms are proved by an example.