The oscillation characteristics of populations in two orthogonal energy substates of semiconductor quantum dots (SQDs) excited by linearly polarized monochromatic pulse field were discussed. With rotatingwave approximation, the nondamped solutions of the dynamic population equations with resonance excitation were deduced. The effective transition dipole moments and effective input pulse area were introduced and their expressions were also given. Theoretical analysis showed that the amplitude and frequency of the population oscillation on the substates can be manipulated by adjusting the original conditions and the polarization angle of excitation field.