In three-body abrasion the relation between wear weight loss and material hardness is more complicated than in two-body abrasion. In order to explain the relation, short-travel three-body, short-travel two-body and long-travel three-body abrasion tests were done. The results showed that: (1) in three-body abrasion cutting wear and plastic deformation wear coexist; (2) when the material hardness changes, the ratio of cutting wear to plastic deformation wear also changes. on the basis of the test results an expression is proposed whereby the relation between wear and material hardness in three-body abrasion can be satisfactorily explained.