In this paper, we propose a substance identification method based on multiple terahertz time-domain spectroscopy (THz-TDS) systems. Spectral data from different THz-TDS systems were analyzed by wavelet transform to remove the noise and baseline. Then, the standardized data can be obtained by mapping the sampling frequencies to the same with cubic spline interpolation, which is used as the feature vector of the support vector machine (SVM). Finally, the spectral identification accuracy can be up to 98.33% with an appropriate kernel function and the optimization parameters based on grid search. These results are meaningful for the eventual practical application of exact substance identification.