Crowding is one of the prominent problems in the recreation areas of Taiwan. Managers have to equip with more and more database for making appropriate decisions. Computer simulation provides fast and accurate tools for providing information for the managers. Therefore, this study tried to apply computer simulation to the park management for more beneficial project for the crowding problem. Most of the crowding research articles emphasize on the visitors' cognition, although density is not the most critical factor for the crowding perception. However, it is a necessary and important management factor. Therefore, this study tried to apply the queuing theory of operation research to predict and discuss visitors' distribution. The Zoo of Taipei City, which is one of the leading education centers in Taiwan, was selected as the testing site. However, the crowding problem during the weekend happens repeatedly. According to the study of The Zoo, the demand of transportation system in the Zoo will be 4000-5000 people in one day at the year 2001, which can not afforded by the existing transport system. The purpose of this study is to: 1.Propose the manageable parameters of visitors' carrying capacity by the simulation, which is a useful tool for the decision-makers. 2.Built the simulation model of the testing site, discuss the process of how to simplifying the real condition to a simulation model. 3.Create a decision-aid system for the recreation capacity problems for the theme park managers by proposing an appropriate management parameters of the theme park. The result shows there are no statistically significant differences between the simulated distribution and real visitors' distribution. This proves the effectiveness of the simulation model. Furthermore, there are no statistically significant differences between real visitors' distribution and visitors' crowding perception at different locations. The result supports the importance of the density factor on visitors' crowding perception.