The simulation technology of 3G mobile communication network is a very important part of network researching. It can increase researching efficiency and decrease developing cost of network. At first, in this paper, we have discussed producing method of some kinds of stochastic numbers, include heavy- tail distributing stochastic numbers, which often used in network simulation. We have also introduced structure of UMTS (Universal Mobile Telecommunication System). Finally, a 3G mobile communication network simulation model has been set up.