  Let G be a non-abelian group and Z(G) be the center of G. The non-commuting
graph {\Gamma}(G) of G is a graph with vertex set is non central elements of G
and two vertices x, y are adjacent if and only if they are commute. In this
paper we calculate the energy, Laplacian energy and spectrum of non-commuting
graph of dihedral group D2n. Also we will obtain the energy of non-commuting
graph of D2n \times D2n and G \times H, where G is a non-abelian finite group
and H is an abelian finite group
