Polypropylene has a wide range of applications in scientific research, industry, and production due to its excellent mechanical properties and chemical stability. However, owing to its low melt strength, inferior dimensional stability, and poor thermal stability, thus limiting its further application. Addressing this challenge, a series of polymer composites consisting of rice husk charcoal (RHC), modified using 3-glycidyloxypropyltrimethoxysilane (KH560) as the silane coupling agent, and polypropylene (PP) have been fabricated by virtue of a melt blending process by us. Thermal behaviour, crystallization properties, mechanical properties, dimensional stability and microscopic morphology of PP/RHC composites are studied in detail. The results show that, when 20% modified RHC was added to the composites, it increased the initial decomposition temperature of PP by 130℃, which represents that we manufactured PP composites with better thermal properties by simple processing. The rheological performance tests showed that the addition of RHC increased the stiffness and dimensional stability of the composites, which is more conducive to the processing and moulding of the material. SEM indicated that KH-560 can increase the compatibility of RHC with PP substrate, thus improving the performance of conforming materials.