This article presents a method for design of improving medical record area in OPD of a governmental hospital case study, Mahasarakham Hospital, Thailand. By using a simulation model which is Petri Nets model for simulating and analysis of coming patients and their relatives in the hospital case study during 6:30-16:00 of the working days. The results found the application was applicable. Recommendations for the design of improving the waiting area case study were discussed and presented in this research.