In terms of the multi-well energy representation technique, the effects of the distance between wells on the valence band structure and characteristics are analyzed for InGaAs/InGaAsP strain-compensated multiple quantum well lasers with zero net strain. The computed result shows that a coupling effect exists between the wells, causes an energy split, and affects the properties of the laser, such as the density of states, optical gain, differential gain, threshold wavelength, threshold carrier density and threshold current density. We find that when the distance between wells equals twice the thickness of the well, the effect of the distance between wells on the characteristics of the laser becomes weak. Therefore, for the practical design of lasers, it is reasonable to take the thickness of the barrier to be twice that of the well.