Abstract: In this paper a method based on data envelopment analysis (DEA) is proposed to evaluate the relative efficiency of plant maintenance.In the method,a systematic functional model is built to analyze the imput/output of plant maintenance,which is processed as a service system,and DEA is applied as a calculating model for plant maintenance evaluation.The method fulfills the systemic and impersonal demand in plant maintenance evaluation and its validity and reliability are demonstrated by the application in a petrochemical enterprise.

Key words: plant maintenance, system modeling, evaluation, data envelopment analysis