Micro/mesopore composite catalysts containing platinum with HZSM-5 zeolite and three different silicate mesopores (SBA-3, KIT-6, and KCC-1) were prepared to investigate the influence of different silicate mesopores in the isomerization reaction of n-heptane at the temperature of 200-350 °C The structural characteristics and morphology of the prepared catalysts were studied by various methods such as XRD, FT-IR, N2 adsorption-desorption, XRF, and SEM. The obtained results indicate that the prepared catalysts have high conversion and high selectivity of multi-branched isomers compared to mono-branched isomers and low development of aromatic compounds. The most suitable results and selectivity were obtained in the n-heptane isomerization reaction related to the Pt/HZSM-5-SBA-3 catalyst.