A high-power LED lamp cooling device and its manufacturing method, which includes: manufacturing a semiconductor crystal bar in advance into cone-shaped crystal bar with one end having large diameter and the other having small diameter, making color mark on each wafer as the large-diameter end surface of the tail end when the cone-shaped semiconductor crystal bar is cut into slices; cutting and pelletizing the conical surface to obtain polygonal cylindrical N-type or P-type semiconductor elements, arranging them in a matrix form between two beryllium-oxide ceramic chips provided with conductive circuits, connecting head end of N-type semiconductor elements to tail end of the P-type semiconductor elements in series to manufacture high-power LED lamp cooling device. The high-power LED lamp cooling device can achieve: good cooling effect, high working efficiency, low energy consumption and capable of reducing light failure of LED lamp, and prolonging service life of the high-power LED lamp.