The work aims to obtain preparation technology of coated Cr/Al2O3 composite powder for thermal spraying use, and investigate the rule of influence of process parameters on structure and properties of composite powder. Nano-alumina aqueous dispersion was mixed with the binder to form colloidal liquid, composite particles of which metallic phase was covered by ceramic phase from nano-alumina agglomerated around the core particles Cr. Optimal preparation process parameters were determined. Effects of process parameters on structure and properties of composite powder were studied with SEM, EDS, XRD and Hall flow meter. Adding some binder and reducing coating times could improve coating effect in the preparation process of core-shell structure. Thickness of the shell of final coated particle was up to 25 μm. With the increase of Cr content, the coating effect decreased while powder fluidity and apparent density improved. With the increase of initial Cr particle size, the coating effect and sphericity increased while liquidity and apparent density change slightly. Adding 5wt% binder for coating one time is the best preparation process parameters of coating Cr/Al2O3 composite powder, the powder prepared in this manner features in uniform particle size, good flow ability and apparent density, hence it is suitable for thermal spraying.