All cross sections of neutron-induced reactions, angular distributions, energy spectra, and double-differential cross sections are consistently calculated and analyzed for n + 27Al reactions at incident neutron energies below 200 MeV based on the nuclear theoretical models. The optical model; the unified Hauser-Feshbach theory and exciton model, which includes the improved Iwamoto-Harada model; and the distorted wave Born approximation theory are used. Theoretical calculated results are compared with the experimental data and the evaluated results in ENDF/B-VII and JENDL-3. The optical model potential parameters are obtained according to the experimental data of total and nonelastic scattering cross sections and elastic scattering angular distributions.