How to effectively organize and store the profile of moving objects in a mobile environment, which can effectively lower the paging and update cost, is an important problem in location management. Combining data mining into a mobile environment is a challenging research task, which has broad prospective applications. In this paper, a solution is provided to optimize the placement of location databases from the aspect of data mining. First a new hierarchical clustering algorithm is presented to cluster the moving log, then use the clustering results to dynamically reunite location databases, thus the paging and update cost can be lowered effectively.