Abstract: Schema integration is a critical step in many database applications, such as data space, data warehousing and electronic commerce, etc. This paper proposed an automatic approach to generate the mediated schemas over a set of source schemas. Firstly, the concept graph is presented to represent the source schemas for the unified representation. Secondly, the similarity between concepts is divided into intervals for the generation of the three merging strategies. Finally, the simulated annealing algorithm is employed to automatically generate the best k mediated schemas. Through extensive experiments, the results show that the algorithm proposed is effective and the running time is little.