A coal material decomposition apparatus includes a sealed rotary kiln body provided with a coal inlet and a coal outlet. A coal decomposition gas collecting pipe is arranged in the kiln body and is provided with two parallel spirals for dividing space in the kiln body into a heating gas bin and a coal material decomposition bin. The coal decomposition gas collecting pipe communicates with the coal material decomposition bin through a gas guide hole arranged in the coal material decomposition bin. As the kiln body is internally divided into the a heating gas bin and a coal material decomposition bin isolated from each other, a large amount of hot gas in the heating gas conducts and radiates the heat to pulverized coal in the coal material decomposition bin, and the pulverized coal fully absorbs the heat to be decomposed into gas, coal tar gas and coal with high heat-value.