A proper k-coloring of a graph G is a mapping from V(G) to a set of k colors such that any two adjacent vertices have different colors. The chromatic number,, is a minimum integer k that G has a proper k-coloring. A coloring c of G is called an injective coloring if for every two vertices u and v which have common neighbor, c(u) is not equal to c(v). That means, the restriction of c to the neighborhood of any vertex is an injective function. The injective chromatic number , denoted by , is the least integer k such that G has an injective k-coloring