The ZSM-5/MCM-41 composite molecular sieves were synthesized in the method of hydrothermal crystallization in the presence of cetyltrimethylammonium bromide (CTMABr) as template agent. The prepared composite molecular sieves were characterized by the means of X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and the thermogravimetric and differential thermal analysis (TG-DTA). The experimental results showed that as-prepared ZSM-5/MCM-41 composite molecular sieves kept both crystal structure and compositions of ZSM-5 zeolites and MCM-41 molecular sieves. The decomposition temperature of the template agent was 293°C, and the decomposition temperature of the molecular sieve framework was higher than 800 °C. We supposed that the obtained ZSM-5/MCM-41 composite molecular sieves had high thermal stability, framework rigidity and structural stability, and could combine the properties of ZSM-5 zeolites and MCM-41 molecular sieves successfully.