The disclosure provides a self-starting circuit and method for a high-order energy obtaining power supply to achieve the self-starting of the high-order energy obtaining power supply. The self-starting circuit includes a current limit circuit, a clamping circuit, a main switch circuit, a switch tube protection circuit, a switch tube drive circuit and a power supply capacitor. The current limiting circuit, the clamping circuit, the main switch circuit and the power supply capacitor are connected in series sequentially. In the serially connected circuit, an upper end of the current limiting circuit is connected with an input positive electrode of the high-order energy obtaining power supply, and a lower end of the power supply capacitor is connected with an input negative electrode of the high-order energy obtaining power supply. The self-starting circuit in the disclosure has the characteristics of wide working voltage range, high voltage resistance, flexibility and adjustability. The self-starting circuit and method prevent hiccup starting of the power supply under low voltage by clamping the voltage with the clamping circuit, can adjust the starting time and voltage of the power supply by changing the current limiting resistance and clamping circuit parameters, can adjust the highest working voltage of the self-starting circuit by changing the number of serially connected switch tubes of the main switch circuit, and have universal applicability.