The present invention provides a LED flat-plate type multi-chip high power light source comprising a heat dissipating substrate, a reflecting cover mounted on the heat dissipating substrate, a circuit board embedded in the heat dissipating substrate, LEDs mounted on the circuit board and in the reflecting cover, and the circuit board also connecting to a socket set in the heat dissipating substrate. The heat dissipating substrate is made of high heat conduction metal. In the present invention, the heat dissipating substrate is made of high heat conduction metal, and the heat conducting pole is abolished. Comparing with the conventional art, the present invention decreases the heat dissipating path, increases the sectional area, and eliminates the intermediate link of high thermal resistance.