The purpose of this study was to predict the future urban activities effectively and rationally. For the purpose, a simulation model, based on SD, was built by integrating economic activities, land use and traffic of a city and by dividing Daegu Metropolitan City into seven districts and one county. To identify the effect of the development of a new city in the Dalsung County area, the future population and traffic volume of the city were predicted, using the model. The results are summarized as follows. The future population according to the development of a new city in the Dalsung County area was predicted, and the effects before and after the development twenty years later were compared. The future population of the Dalsung County was found to have slightly increased, whereas that of the adjoining Dalsuh Metropolitan District was found to has slightly decreased. For the other districts, there were no changes of the future population. It was found, therefore, that the development of a new city would have no effect on other districts. Then, the traffic volume according to the development of a new city in the Dalsung County area was also predicted. It was found that in the initial stage the traffic volume would increase with the increase in population of Dalsung County. It was predicted that particularly,. the traffic volume for the purpose of business would greatly increase. The traffic volume of Dalsuh Metropolitan District showed a slight decrease, whereas for the other districts, there were no changes of the traffic volume.