In numerical modeling of the plane detonation wave,the state behind steady detonation must be in agreement with the Chapman-Jouguet theory. The modified JWL equation of states (EOS) of the products and Hybrid reaction model are used to obtain the matching relation between artificial viscosity and mesh size of PBX9502 of insensitive high explosives and are compared with other reaction models. When this condition is satisfied,the detonation velocity and the state of sound speed point including pressure,density and internal energy can be in agreement with the C-J theory. These variables are independent of mesh size. Thus the mesh size can be larger,and the matching relation can be used in practice.