The CoCrFeMnNi high-entropy alloy is a promising erosion- and wear-resistant coating for fracturing pump valves due to its exceptional toughness, hardness, and corrosion resistance. Molecular dynamics simulations of indentation, scratch and impact under high stress reveal that polycrystalline and polycrystalline twin structures exhibit poor erosion resistance due to grain and twin boundary-induced stress concentration. In contrast, the (111) crystal plane in single-crystal structures excels in hardness and wear resistance, benefiting from its triangular atomic arrangement and superior load buffering capacity. However, under severe conditions, the (111) plane generates more surface wear atoms and internal defects, posing risks to pump valve substrates. These findings provide a theoretical basis for optimizing coating selection in engineering applications. Graphical Abstract