A bipolaron microscopic model is proposed in this paper to interpret theoretically the Raman scattering data in cis-polyacetylene on the basis of lattice relaxation theory. The coupling of electron to different phonon modes is taken into account, the coupling constants being determined from the infrared and the Raman data. The theoretical results thus obtained are compared with the experimental data and discussed. The method used in this paper can be generalized to other similar systems.