Schema matching is a basic problem in many application fields as fundamental operation of schema. This paper analyses the advantages and limitations of iMAP and CM, and proposes an extended schema matching system architecture between Database Schemas (ESM). First, ESM filters unreasonable matches by preprocess and clustering process. Then it employs a set of special-purpose searchers to explore a specialized portion of the search space and discover 1:1 and complex matches. Then it estimates candidate matches and selects optimal candidate matches by using similarity estimator and match selector respectively.