This article induces the key points and test principles of the developed the digital carpet electrostatic tester, which is used to measure the electrostatic charge amount generated by the friction between the shoes and the carpet when people walking on the carpet. The design of the hand-held electrode is based on the principle of capacitor divider. The paper proposed a static calibration based on the piecewise linear interpolation method. The specific points are dynamic calibrated with a point to point method. After being calibrated, the measuring accuracy of the instrument is effectively improved. Then the signals collected by the instrument is processed with mean filter, which can effectively solve the singular signals caused by the inconsistent of the sampling frequency and the people walking frequency. Experiments of two different kinds of carpet samples are conducted in the same condition to evaluate the electrostatic property. The result proves that the digital carpet electrostatic tester provide a comprehensive evaluation method of the carpet electrostatic property.