A series of In2O3-beta composites with different contents of zeolite beta were prepared by the deposition–precipitation method, followed by calcination at 700 °C, and their catalytic performance in the conversion of ethanol to propylene (ETP) was investigated. The physicochemical properties of the as-synthesized materials were characterized by XRD, N2 adsorption, SEM, NH3-TPD, CO2-TPD and a probe reaction. The combination of In2O3 and zeolite beta improves the propylene yield significantly. The optimal result was observed for the composite with a beta content of 20–50%, which gave ca. 50% yield of propylene. The role of beta in the In2O3-beta composite catalyst is to promote the conversion of the intermediate of acetone to propylene via an additional reaction pathway, which accounts for the superior propylene yield of the In2O3-beta composite in comparison with In2O3 (ca. 32%). The proximity of these two components (In2O3 and zeolite beta) plays a crucial role in achieving a high yield of propylene for the ETP reaction.