MDA is one of the major trends in software development. The intergration of MDA and HLA is helpful to overcome the inherent shortcomings of HLA, prolong the HLA system life and make the HLA system easier to adapt to new simulation demands. This paper researches on the integration methodology of MDA and HLA system without modifying or rebuilding the old HLA system. It tries to rationalize traditional MDA modeling process and proposes a methodology with which MDA can be applied to the old HLA system. At last, it successfully transformed MDA model to HLA model with XSLT.