Broadband network measurement is an important means to obtain the electrical characteristics of microwave and millimeter wave devices, and the TRM calibration method is widely used in the calibration of broadband network measurement systems. In order to effectively evaluate the accuracy of the measurement data, it is necessary to analyze the uncertainty of the TRM calibration and measurement. The principle of small-signal calibration and error correction based on 8-term on wafer measurement is explained. Based on this, the uncertainty propagation formula of the TRM calibration method is pushed, which can effectively evaluate the non-ideality of each calibration kits. Effect of calibration results. The verification experiment was performed by using a transmission line with known parameters as a non-ideal straight-through calibration kit. The experimental results show that the uncertainty propagation formula can accurately evaluate the error of the measurement data, and the maximum difference does not exceed 0. 02 dB.