Abstract: The directional derivatives and subdifferentials of set-valued mappings are studied by scalarization approaches. With the help of the Gerstewizt function, the concepts of Michel-Penot directional derivatives and Michel-Penot subdifferentials of set-valued mappings are introduced. Their properties are studied and their calculus rules are established. As application, optimality conditions for unconstrained set-valued optimization problems are given by Michel-Penot subdifferentials.