The high entropy alloy coating was successfully prepared on the surface of 45_^# steel matrix by cold spray assisted in situ synthesis of FeCo_xCrAlCu (x =0,0.5,1,1.5,2) high entropy alloy coating. The effects of Co content on phase structure, microstructure, hardness, wear resistance and corrosion resistance of alloy coating were analyzed by XRD,SEM,EDS,TEM, microhardness meter, abrasive wear testing machine, electrochemical workstation and so on. The results show that the alloy coating was composed of simple FCC+BCC two phase mixed structure, and the change of Co content has little influence on the amount of phase structure of the coating.With the increase of Co content, the number of dendrites in the microstructure of the alloy coating increased and got obvious coarsening.The number of crystals had increased, and it had been significantly coarsened. The microstructure was enriched with Fe, Cr, Co in the dendrites, and Cu was enriched between the dendrites, and Al was evenly distributed in the entire coating.With the increase of Co content, the hardness first increased and then decreased. When Co=1, the hardness of the alloy coating reached a maximum of 555.6HV.The minimum friction coefficient in the alloy coating is 0.361.In 3.5wt.%NaCl corrosive medium, the alloy coating had a positive self-corrosion potential compared with the 45_^# steel substrate (E_corr=-0.325V), indicating that the coating had better corrosion resistance than the substrate.