Many IT specialists say that ERP (Enterprise Resource Planning) is the best way to manage resources in enterprise effectively Lots of companies are using ERP solutions in the hope of getting competitiveness and employing global standard business practice. Wishing to take advantage of ERP S/W, companies have a preference for purchasing it and outsourcing ERP project. This paper focuses on ERP Package assessment model in business firms. This paper finds out what differences there are in purchasing ERP S/W for organization characteristics and building characteristics, and suggests some guidelines of S/W development to vendors. The results would be strong implications for ERP vendors. Especially this paper identifies what the reasons and the checkpoints are when firms introduce ERP S/W. To do this, this paper uses empirical data obtained from companies in South Korea and analyzes it using statistical software.