There are more than 400 species of termites in China, most of which are primarily dwelling in the south China. Coptotermes formosanus Shiraki is one of the main harmful species in these termites which may cause extensive damage to buildings and living trees. In order to explore the relationship of soil pH value and the survival as well as the feeding behavior of C. formosanus, we evaluated the effects of yellow clay at the pH range of 1.7-10.8 on the living of C. formosanus. The results showed that C. formosanus may penetrate the clay with pH values at the range of 3.0-10.1, and feed on the wood blocks surrounded with such clay. Both the ability of penetration in the clay and the consumption of wood blocks decreased with the increase of soil pH values. Based on the prediction with the stepwise regression equation, the range of soil pH value which C. formosanus could not penetrate was <1.85 and >10.91.