To study the effect of steam explosion conditions on the chemical components of tobacco stalks and to construct a correlation model between the chemical components of tobacco stalks and steam explosion power density (EPD) and blasting intensity factor (R0), the steam explosion was carried out at different pressures, with different water content and times. The contents of polyphenols (chlorogenic acid, rutinoside, and scopoletin), cell wall substances (cellulose, hemicellulose, lignin, and pectin), and conventional compounds (total sugars, reducing sugars, and total phytobasic alkaloids) in the treated samples of tobacco stalks were determined. The correlation models between the chemical components of the stalks and the EPD and R0 were constructed. The results showed that total sugars and reducing sugars were most affected by the steam explosion pressure, pectin, and total phytate were most affected by the water content of tobacco stalks, and pectin was most affected by the steam explosion time. EPD and R0 had a more significant effect on the content of chemical components of tobacco stalks, and the impact on different chemical components was also different. In the correlation models constructed for the chemical fractions of tobacco stalks with EPD and R0, the correlation R2 reached more than 0.9, and the degree of correlation was high. This study can provide essential theoretical support for the degradation of cell wall materials, chemical composition transformation, and other characterizations after steam explosion treatment.