A design has been developed of the auxiliary power supply of the half-wave rectifier circuit based on UC3843. A brief introduction has been made of the operation principle of the half-wave rectifier circuit, followed by some relevant quantitative calculation and comparison with the acquisition way of the traditional auxiliary power supply. This principle has been applied to the design of the actual circuit, as well as to the LED constant-current driver, with 12 V the output voltage of the half-wave rectifier circuit. The test result of the prototype shows that the performance of the designed auxiliary power supply of the half-wave circuit based on UC3843 meets the design requirements, thus worthy of the market-oriented promotion.