In this work, medium and high entropy alloy coating was prepared on the surface of 38CrMoAl by laser cladding technique. The effects of adding elements such as Al, Si, Fe, and Nb to CoCrNi series alloys on the phase, microstructure, and element distribution of the alloy coating were studied. The hardness, wear resistance, and electrochemical properties of the coating were analyzed and characterized. The results indicate that CoCrNi alloy has a face-centered cubic (fcc) crystal structure, and the addition of Al and Fe promotes the formation of body-centered cubic (bcc) phase. After the addition of Nb and Si elements, a Laves/bcc eutectic+Nb-riched composite phase is formed in the septenary-element-alloy coating, and the microstructure is significantly refined. The comprehensive performance of CoCrNi-based medium and high entropy alloy coatings is superior to that of 38CrMoAl substrate. Compared with CoCrNi and AlCoCrFeNi alloy coatings, the hardness, wear resistance, and corrosion resistance of AlSiCoCrFeNiNb coatings have been significantly improved: the surface hardness is 713.3 HV0.1, which is 3.24 times higher than that of the substrate. The wear mechanism is mainly slight abrasive wear and adhesive wear, with an average coefficient of friction of 0.52 and a wear rate of 115.73×10–12 mm3/(N·m), reduced by 64.4% compared with that of the substrate. The self corrosion potential (Ecorr) is –0.3392 V, and self corrosion current density (Icorr) is 0.472 μA·cm-2.