SMEs(Small and Medium-sized Enterprises) have implemented the various IT-based Production Information Systems(PIS) to cope with the highly competitive environment as well as to improve their competitiveness and productivity. For the efficient development of PIS In SMEs, standardizing the system development process is required. Methodology for the development of PIS is especially important for the systematic and efficient implementation to communicate among the SI companies, SMEs, and a supervision agency. TIPA(Korea Technology and Information Promotion Agency for SMEs) has developed PSDM(Production System Development Methodology), and supplies it to the SI companies. The research goal of this paper is to explore the productivity improvement by adopting the PSDM with the cases of SI companies applied PSDM. The results show that such benefits as risk management, productivity improvement, easy system implementation and maintenance are perceived by PSDM Users. This research could be the first case study reveal the effectiveness of PSDM. For further research, the survey could be carried out with more samples.