Abstract: In this paper, in order to solve the problem of site zoning for urban district, which lack of Investigation data in planning urban hazardous prevention, method of estimating site category based upon Bayes theorem is adopted by means of seismic and site information of those sites that have been classified and zoned in the involved city. Furthermore, site zoning can be gained by further integration with the seismic geological, engineering geological and ground surroundings' information. The example of Quanzhou city is presented subsequently, and basic procedure of site zoning by using this method is brought forward, too. This methodology has been applied in planning of Quanzhou and Xiamen with good effect.