An acyclic coloring of a graph G is a proper vertex coloring ( no two adjacent vertices of G have the same color) such that the induced sub graph of any two color classes is acyclic. The minimum number of colors required for acyclic coloring of a graph G is called as its acyclic chromatic number and is denoted by a(G). In this paper, we present the structure and coloring algorithm of central graph of Gear Graph Gn and we obtain the exact value of its acyclic chromatic number.