In the experiment of measuring resistance by voltammetry ,it is usually to measure the voltammetriccharacteristic curve of resistance.ln order to make full use of the measuring accuracy of the ammeter,it isusually necessary to change the ammeter range.However,the internal resistance of the ammeter also changes.How to consider the error caused by ammeter range change is an important problem in this experiment.Aoiecewise correction function is introduced to overcome this problem.Accordingly the influence of the change otammeter resistance on the measurement accuracy is considered self-consistently, which makes the dataorocessing method more reasonable.