  The study of $n$-Lie algebras which are natural generalization of Lie
algebras is motivated by Nambu Mechanics and recent developments in String
Theory and M-branes. The purpose of this paper is to define cohomology
complexes and study deformation theory of $n$-Lie algebra morphisms. We discuss
infinitesimal deformations, equivalent deformations and obstructions. Moreover,
we provide various examples.
