A new plate-type high power LED illuminator with louvers is designed. It has the features of light weight,small size,beautiful appearance,modularization and reconfiguration. Aluminum plate with high thermal conductivity is applied as radiated circuit plate for high power LEDs,and aluminum stack with 0.4 mm thickness as radiated fins,which make illuminator module with input power 21 W combining with micro grooved heat pipe. The illuminator module is integrated with lightening and radiating. According to lumination requirements,module groups can be reconstructed into illuminators with different input power. Theoretical analysis and experimental research were conducted to a 144 W illuminator. Calculated results indicate the calorific value of one module is 18 W and the heat transfer value is 47 W. The simulated results indicate that the max junction temperature (Ta) of LED chips is 75 ℃ and Ta measured by experiment is 75.7 ℃ when ambient temperature is 30 ℃ and natural convection heat transfer coefficient 10 W/(m2·K). Theoretical calculation and simulated results show that the illuminator has a good prospect of application and can be used as street lamp,square headlight and so on.