The purpose of this study is to explore an efficient method of preparing zirconium alloy surface coating for nuclear power cladding material, in order to improve the high temperature oxidation performance of zirconium claddings resisting sever accidents. Due to the advantages of dense coating, high bonding strength and low oxidation, High-velocity oxy-fuel (HVOF) thermal spraying was used to prepare Cr coating on Zr-4 alloy. Microstructure was observed by X-ray diffractometer (XRD) and scanning electron microscopy (SEM) coupled with energy dispersion spectroscope. The adhesion between Cr coating and substrate was measured by scratch tests, The macro-scratch morphology was observed by optical microscopy (OM). Results show that Cr coating prepared by HVOF is composed of Cr with body centered cubic (bcc) structure and approximately 21.9% Cr2O3 with hexagonal close-packed (HCP) structure. Polishing can reduce the Cr2O3 content to about 10.1%. The morphology of Cr coating consists of un-melted white particle and lamellar structure in majority and pores in minority. Cr2O3 is mainly distributed in the layered structure, and the irregular massive structure formed by un-melted particles containing little oxygen is mainly Cr metal. Adhesion between Cr coating and substrate if of 77 N in minimum and 94 N in maximum. The maximum adhesion is 94 N under the spraying process with parameters of kerosene flow rate of 23 L/h, oxygen flow rate of 880 L/h, and coating spraying distance of 330 mm. The oxidation test in air at 1 200 ℃ for 30 min shows that a mutual diffusion layer about 14 μm to 16 μm is formed. The mutual diffusion layer consists of a compact Cr-Zr layer approximately 11 μm to 14 μm containing Zr in coatings next to the interface of matrix and approximately 5 μm dark Zr-Cr layer the matrix next to the interface of the coating. This indicates a faster diffusion of Zr from the matrix to the Cr coating than that of Cr from the coating to the matrix. Cr coatings prepared by HVOF oxidized little after the exposure of air at 1 200 ℃ for 30 min. Zr matrix covered by Cr coatings covered by Cr coating is not oxidized while oxide films of Zr matrix uncovered with Cr coating is above 120 μm in thickness, which illustrates that Cr coating prepared by HVOF has an excellent protective property to Zr matrix.