The performance simulation of micro-channel condenser for air-conditioners has been conducted with variation of refrigerant flow pass structures and flow depths of heat exchanger. Effectiveness NTU method for cross flow heat exchanger was used for calculating heat transfer rate. Heat transfer coefficients and pressure drops for two-phase flow inside micro channel tubes were calculated by the Shah and the Friedel correlations respectively. The heat transfer coefficients for louver fin were measured experimentally. The performance of condensers depended on the structures of refrigerant flow passages.