In this paper, in order to enhance the thermal performance of sodium acetate trihydrate (SAT) in thermal storage, novel composite phase change materials (CPCMs) that contains SAT (as PCM) and silicon carbide (SC), bentonite (as additives) were prepared. The microstructures, chemical structures, leakage performances, phase change properties, thermal stability and thermal energy storage performances of the CPCMs were investigated. The experimental results indicate that the bentonite is helpful to solve the leakage problem. The supercooling phenomenon and thermal conductivity of SAT are improved by adding SC. In addition, compared with those of pure SAT, the heat storage time and release time of SAT/bentonite/SC CPCMs are shorten by 25.44% and 78.5% respectively when the mass fractions of bentonite and SC of the CPCMs are 26 wt.% and 10 wt.%. The research results exhibit a reference value for improving the thermal performance of SAT in thermal energy storage process.