Voltammetry is a common method for measuring resistance, the resistance error sorter is a widely used measuring instrument. In some specific applications, users have special interest on the deviation of the measured resistance relative to a reference resistor. The purposed design is based on such specific application requirements and to develop a resistance error measuring instrument. The measuring instrument uses a constant current power supply, the measured value is processed by the operational amplifier, the analogtodigital converter, and presented in an intuitive digital form. The instrument haslow measurement error and easytouse features. By analyzing the frontend signal processing circuit of the measuring instrument, this article explains the design scheme, structure principle and component selection basis of the instrument. It discusses the additional error of the measurement results caused by the local circuits, with a quantitative estimatation of the size of the error, and provided counter measures in this regard. Eventually, the analysis of the test error calculation proves that the measuring instrument has met the measurement accuracy requirements.