In this paper, we introduce the concept of (f,g)-derivation, which is a generalization of f - derivation and derivation of ordered $\Gamma$-semiring and study some properties of (f,g)-derivation of ordered $\Gamma$-semirings. We prove that, if $d$ is a (f,g)-derivation of an ordered integral $\Gamma$-semiring $M$ then $\ker d$ is a $m-k-$ideal of $M$ and we characterize $m-k-$ideal using (f,g)-derivation of ordered $\Gamma$-semiring $M$.