High-power LED is gradually replacing traditional illumination source for streetlight because of the advantages of compact size, low pollution, high durability, and high efficiency. Therefore, in this paper a high-power LED streetlight with an integrated forward-flyback converter and energy regenerative snubber is proposed, and a digital signal processor is used as the control core. The proposed circuit is with primary-side and quasi-resonant regulation, so the system size and the switching loss can be effectively reduced; besides, the overall system performance is improved. Additionally, digital pulse-width modulation is employed for the luminance control. Finally, the Taguchi method is employed to optimize the parameters of the driver transformer and output inductor and the converter efficiency. The test results of the converter performance and the optical properties of the prototype circuit confirmed the feasibility of the proposed circuit and the parameter optimization method.