The thermal decomposition of wood treated with a series of silicates was characterized by thermogravimetric (TG) analysis, differential thermogravimetry (DTG), and thermogravimetry–mass spectrometry (TG–MS) analysis. The addition of these chemicals caused a decrease in the decomposition temperature, a reduction in weight loss, and an increase in the amount of char produced. The results showed that ion current intensity and ion peak area of the typical representatives of incombustible ion such as m/z = 18 and 44 MS signals were increased by the flame retardants but the inflammable ion such as m/z =12 and 28 MS signals were decreased at the meantime, which indicate that the flame retardants can significantly enhances the dehydration and inhibits the deploymerisation reaction of wood.