本文采用锁相放大器测量电阻热噪声，获得玻耳兹曼常量，其物理原理较容易被学生理解，其实施则需要高精度测量技术支持和学生对锁相放大器测量原理及其仪器参数含义的清晰理解. 针对物理学专业、尤其是精密测量物理专业的特点和需求，本文尝试尽量不涉及电子技术知识，而侧重用数学描述锁相放大器测量噪声的原理，包括电阻热噪声表达式、锁相放大器处理噪声的过程、等效噪声带宽的推导，并基于误差分析优化玻耳兹曼常量测量的教学实验设计，最后简要介绍初步教学实践情况.

The teaching method of obtaining Boltzmann constant by measuring the thermal noise of a resistor with a lock-in amplifier is easy for students to understand in physics, and its smooth implementation requires technical support of high precision measurement and students’ clear understandings of the measurement principle and the meanings of instrument parameters of the lock-in amplifier. To meet the peculiarity and the requirements of physics specialty, especially that of precision measurement physics, it is tried to avoid as much as possible involving in knowledge of electronics, but focus on mathematical description of noise measurement with a lock-in amplifier, including the derivations of thermal noise of a resistor, the noise processing process of a lock-in amplifier, and the equivalent noise bandwidth. The experimental design of Boltzmann constant measurement is optimized based on error analysis. Finally, the preliminary teaching practice is briefly introduced.