To obtain the coupling characteristics between slab wave-guides including left-handed material,we modify the coupled wave equations by using Maxwell’s equations. First,we obtain new-coupled wave equations and new-coupling coefficient. Second,the coupling between two identical five-layer slab wave-guides where their cores are left-handed material,but their claddings are right-handed materials is studied. The coupling coefficient for even TE mode which is more complex than that of the riglt-handed material slab wave guides,is obtained.