从中学物理教学实际出发,联系当前高考动向和学生学习情况对电学试验中的伏安法测电阻时的误差及误差来源这一个重要问题作一个简要概括。主要从应用部分电路欧姆定律和全电路欧姆定律测外电路电阻和电源电阻两方面讨论,其中又牵涉安培表外接法和内接法时误差来源不同,本文一并探讨。应用方法包括运用公式和应用图像两种。 Starting from the actual teaching of middle school physics, this article gives a brief summary of the important problem of the error and the source of error when measuring the resistance by the voltammetric method in electrical test in connection with the current college entrance examination trends and student learning. Mainly from the application of part of the circuit Ohm’s law and the whole circuit Ohm’s law to measure the external circuit resistance and power supply resistance both discussed, which also involves the ammeter external and internal error sources when the error, the paper discussed. Application methods include the use of formulas and application of two kinds of images.