At present, the Korean electricity industry is undergoing restructuring and the Cost Based-generation Pool(CBP) market is being operated preparing for Two Way Bidding Pool(TWBP) market open. As the circumstance of the traditional system is changed according to power system deregulation, the simulation tool which should reflect market code providing market operating mechanism is needed to analyze an electricity market. This paper presents the development of an unique market simulator, Market Modeling and Price Simulator(MMPS) that is designed to imitate the Korean electricity market considering uniform price. The MMPS is developed in VB.NET and is composed of two modules that consist of market modeling and price simulation interfacing access database program. To evidence the features and the performance of MMPS, a small two way bidding market with 12-bus system and one way bidding market for generator competition will be presented for the electricity market simulations using MMPS.