The ultra-relativistic quantum molecular dynamics (UrQMD) model is developed for neutron spallation production from ≈1 GeV proton-induced reactions. Improvements in the dynamical content of the standard UrQMD model include: (i) an initial ground state which reproduces the experimental root mean square radii; (ii) a momentum-dependent Pauli potential and (iii) medium-modified angular distributions for quasi-inelastic NN scattering and the reverse NΔ → NN reaction. It is shown that, in conjunction with the generalized evaporation model, the improved UrQMD model is able to reproduce the whole energy-angle neutron double differential cross sections in the interactions of proton on Al, Fe and Zr at 1.2 GeV.