The energy equilibrium model—The stability theorem on the strained quantum well structure materials have been introduced in the paper. Some typical photoluminescence spectrum related to the crystal quality degeneration also have been reported. They calculated the critical elasticity stress of some ordinary strained multiquantum well structure materials

and pointed out that the in strained cap layer will increase the critical stress of well layers. The difference between the allowed stress in fact and the calculated one have been discussed for the first time.