This study proposes a spectral simulation method for calibrating the light source of TVM based on a digital micromirror. The skew nature of the spectral simulation unit is analyzed, and Bigaussian, Asym2Sig, and ECS functions are selected to fit the positive, normal, and negative skew distribution spectral simulation units, respectively. The spectral simulation comparison experiment between using the Gaussian function and combining the Bigaussian, ECS, and Asym2Sig functions is performed; the spectral simulation errors of the two functions are 33.4% and 25.2%, respectively. This shows that the Gaussian function can be replaced with a combination of three functions for spectrum simulation. The analysis reveals that the main factors influencing the spectral simulation errors are the presence of superimposed regions of spectral simulation units on the surface of the digital micromirror array and the lack of independent control of each simulation unit. The correctness of the spectral correction method based on the maximum simulation error is demonstrated using the local band of 410-460 nm. The final simulation error of the 2700 K color temperature spectrum in the band of 380-780 nm is 6.2%, which is 4.06 times higher than the overall spectral modulation capability before the correction; simulation accuracy of 2700K color temperature spectrum corrected by experiment satisfies the ICAO observation accuracy requirements for the simulation error of 2700 K color temperature spectra at 50 m baseline and provides a research basis and technical support for establishing TVM calibration and traceability chain that satisfies the definition of MOR and the standard of ICAO.