In0.53Ga0.39Al0.08As/InxGa1-xAs0.9Sb0.1 quantum well band structure has been calculated with the effective-mass model and 4×4 Luttinger-Kohn Hamiltonian matrix method. The relations of C1-HH1 transition wavelength versus In composition and well width have been obtained and discussed. Mechanical equilibrium model has been used to calculate the critical thickness for the strain material system. It is concluded that by appropriate structure design and adjustment of composition and quantum well parameters, the InP based InGaAlAs/InGaAsSb strained laser system can readily realize laser radiation in the wavelength range of 1.6～2.5 μm.