The uv-vis absorption and resonance Raman spectra of all-trans-β-carotene in polar solvent 1, 2-dichloroethane with iodine are measured at 293 K. The results indicate that the absorption peak of all-trans-β-carotene in the complex disappears at 460 nm and instead a new peak of the complex formed by all-trans-β-carotene and iodine is found at 1000 nm, so that the all-trans-β-carotene within the complex cannot produce the resonance Raman spectrum by 514.5 nm excitation laser. The Raman scattering cross section of CC bonds of all-trans-β-carotene taht does not form in complex decreases, its full bandwidth broadens and electron-phonon parameter increases with the increase of concentration of the complex, because when the concentration of the complex increases, the disorder increases in the solution and the molecular structural order decreases. These phenomena are analyzed using the coherent weakly damped electron-lattice vibration mode, the effective conjugation length mode as well as the theory of amplitude mode in this work.