According to the characteristics of high moisture content and low calorific value of sludge, an innovative co-combustion method of sewage sludge and rice husk was proposed. The method provided a theoretical basis for the resource utilization of sewage sludge. Through thermal analysis technology, the changes of thermogravimetric and derivative thermogravimetric at different temperatures with various ratios of mixed combustion materials were investigated. Then, the corresponding dynamic model was established to analyze the dynamic mechanism of the co-combustion material. The following conclusions were obtained: First, the combustion of mixed fuel when the amount of sludge is less than 30% is beneficial. Therefore, the use of sewage sludge as fuel to combustion is possible. Moreover, the kinetic mechanism of the combustion reaction can be divided into four processes, that is, one-dimensional diffusion, chemical reaction, one-dimensional diffusion, and three-dimensional diffusion.