Neutron nuclear data on 28;29;30 Si have been calculated for the evaluated nuclear data library JENDL-4. Simultaneously calculated are the total, elastic and inelastic scattering, and ðn; pÞ, ðn; Þ, ðn; Þ, ðn; 2nÞ, ðn; 3nÞ, ðn; npÞ, and ðn; nÞ reaction cross sections, the angular distributions of emitted neutrons, and the energy distributions of emitted particles and -rays. The statistical model was applied to calculate these quantities. Coupled-channel optical model parameters were obtained so as to reproduce measured cross sections. Preequilibrium and direct-reaction processes were taken into account in addition to the compound process. It is confirmed that the present calculations are almost consistent with available experimental data. The calculated data are compiled into JENDL-4.