Abstract: As an important component of modern power systems, smart meters rely on high-precision analog-to-digital converter(ADC) sampling circuits for their core functions. Explored the key role and optimization strategies of sampling circuits in smart meters. Firstly, the paper introduces the basic theory of ADC, including its working principle, classification, and the influence of sampling rate and resolution, laying the theoretical foundation for subsequent discussions. Secondly, the design framework of the sampling circuit and the selection of key components were discussed in detail, and a series of optimization strategies were proposed to solve the problems in current circuit design, improve sampling accuracy and stability. Next, the optimized sampling circuit was evaluated through practical application cases, and its application effect in smart meters was analyzed. Improvement suggestions were proposed.