Three nickel-loaded silica-alumina (Ni/Si-Al) catalysts of varying Si/Al molar ratio (Si/Al ratio) were prepared for catalytic pyrolysis of municipal waste plastic. Acid properties of the catalysts have been analyzed by Fourier transform infrared spectroscopy, and the results showed that the total acid amount increased with the decrease of Si/Al ratio. The temperature and the catalyst acidity have a significant effect on the lump (gas, gasoline fraction, heavy oil fraction, and residue) yields. In addition, the gasoline fraction products that evolved have been analyzed by gas chromatography spectrometer. It showed that the gasoline fraction has higher iso-paraffins and a smaller concentration of olefins and aromatics for a lower Si/Al ratio and higher acidity of catalyst. These results suggested that the proper selection of the Si/Al ratio makes it possible to control the composition distribution, yields, and gasoline fractions of fuel.