The ground and the excited states for the nondegenerate polymer such as cis-PA have been studied using the Kronig-Penney model with unequal potential barriers in the real space. The electronic states，the electron density distributions，and the lattice distortions in the system with different states are obtained. By comparing with those obtained in the Su-Schrieffer-Heeger (SSH) model，we find that our results of electron state densities and electron density distribution are more precise.