Alignment errors of birefringent retarders and retardation errors introduced by environmental perturbations can cause significant influences on reconstructed Stokes parameters for the channeled spectropolarimeter. In this paper, we propose what we believe is a novel self-correction model that is independent of input polarization parameters to reduce the effects of alignment errors and environmental perturbations. This self-correction method can realize calibration and compensation of alignment errors and retardations simultaneously by measuring the target light in orbit. Simulation results show that alignment errors and retardations can be calibrated accurately, and the reconstructed Stokes parameters by using the presented method are more precise than by using the traditional method. The validity and feasibility of the presented method are further confirmed through experiments in the presence of alignment errors and environmental perturbations.