The 170.0°±１．５° backscattering cross sections of 4He from C were measured in the energy range of 5.0-9.OMeV. The R-matrix was used to analyze the scattering cross sections, thus energy level parameters of the compound nucleus 16O, for alpha energies from 3.224MeV to 10.544MeV, were identified. These level parameters can be used to calculate the cross sections at certain angles according to the real experimental conditions The behaviour of a narrow strong resonance at 4.250MeV was inspected at different energy smear and scattering angles of 1650 and 1700. In the two energy regions: 3.600-4.200MeV and 6.425-6.700MeV, the cross sections exhi-bit a smoothly in creasing variation The messured and calculated cross sections show that in the energy range of 3.60-4.20MeV region, the cross sections are not significantly influenced by the scattering angle, but in the energy range of 6.425-6.700MeV region, the cross sections are strongly angle-dependent.