A typical cavitation erosion resisting sample,the weld deposited coationg of boronic stainless steel, and a typical erosion and abrasion resisting sample,the weld deposited coating of WC ceramic are micro-analyzed and studied by means of light microscope, scanning electron microscope(SEM) ,electon probe and X-rays diffraction. The obtained results indicate that the weld deposited coating of boronic stainless steel has better resistance to cavitation eroion, while weld deposited coating of WC ceramics is a better barrier to erosion and abrasion. Forthermore,the material failure from erosion and abrasion is resulted from the combining actions of the minus pressure because of bubble crumbling and the tangential componental force caused by the dashing of silt granular.