Abstract: Taking the sludge of a Liaoyang sewage treatment plant as an example, a fermentation device with control system was designed to carry out the thermophilic aerobic composting process. The best combination of different index can be obtained by analyzing the parameters such as temperature, water content, pH value, EC, WSOC and NH4⁺-N of thermophilic aerobic composting process. The investigation shows that it is a better way to dewater the sludge through natural air-drying followed by mixing with conditioners. Among the sawdust, rice husk and rice straw, the compost can achieve the best maturity with sawdust. The best ratio of sludge, sawdust and returned sludge is 3:2:3. Finally, the sludge treated by the thermophilic aerobic composting process can be defined maturity and applied widely according to the experiments of seed germination.