In order to improve the efficiency of quantitative analysis of ash and volatile content in coal and reduce pollution, a method for quantitative analysis of coal ash and volatile content based on THz Time Domain Spectroscopy(THz-TDS) is proposed. In this paper, the relationship between terahertz absorption characteristics and ash content in coal is studied. The results show that the effective spectrum range of coal is 0.2~2.2 THz, and there is no obvious absorption peak in 0.2~2.2 THz; the ash content is the main factor affecting the absorption characteristics of the terahertz band. The effects of preprocessing methods, Support Vector Machine(SVM) model and Partial Least Squares(PLS) model on the prediction effect are compared. The results show that Savitzky-Golay smoothing and Moving Average Filter(MAF)smoothing do not improve the prediction effect of external validation sets, and the prediction effect of SVM model on ash and volatile content is better than that of PLS model. The correlation coefficients(R p) and Root Mean Square Error of Prediction(RMSEP) of the external validation set of ash and volatile of SVM models are 0.933, 3.223, 0.724 and 5.772, respectively. The terahertz technology combined with SVM model can predict ash and volatile content in coal, and the analysis time can be shortened to be less than 10 minutes, which has improved the analysis efficiency.