Abstract:Compared with the measurement uncertainty evaluation of traditional instruments, the measurement function model introduced by the virtual instrument hardware is complex, and the measurement uncertainty is difficult to be measured due to the instability of the software .GUM did not give the evaluation of the uncertainty of such measurement process. Paper introduces the concept of NI virtual instrument and Calibration Executive Calibration software. Taking PXI-4070 as an example, this paper focuses on analyzing the source of uncertainty introduced by the hardware, realizes the synthesis simulation of each component source on Labview platform, implements the Calibration simulation program with the high-precision multi-functional standard source, and Bisquare method fit the measurement results to obtain the polynomial mathematical model. Regression to gum method to realize uncertainty evaluation of measurement results of virtual Instrument.