Ontology mapping is a key technology to resolve interoperability between heterogeneous and distributed ontologies. So far, many efforts have been conducted to suggest ontology mapping model. The RFCA mapping model is one of them. In this paper, the problem of the reduction of formal context in the mapping process of the RFCA model is addressed, and a method using Attribute Reduction to enhance the RFCA ontology mapping method is proposed. With Attribute Reduction, the RFCA method can be adaptable to the large scale of ontology mapping. Our experiment has illustrated that this method is feasible.