This paper, based on diffusion theory of crystal-lattice atoms , analyzes the diffusion laws of III & V family atoms in the InGaAsP semiconductor material . The theory model of quantum well intermixing (QWI) in quantum wells and super-lattice are established. The relations of component material and strain with diffusion length are computed by simulation , and the strained effects to quantum wells band-gaps, band-edge structures and quantum jump are computed and analyzed. Some valuable results are obtained which supply the principal theoretical basis for researching and developing quantum wells and super lattice devices.