We report here the measurements of valence electron structure for the n-butane (C4H10)using high resolution (E=0.9 eV FWHM, P=0.1 a.u.) (e,2e) spectrometer. The impact energy was 1200eV plus binding energy (i.e. 1206 to 1232 eV) and symmetric non-coplanar kinematics was employed. The inner-and outer-valence energy spectrum is in agreement with published Photoelectron data. The experimental momentum profiles have been compared with calculations obtained using Hartree-Fock method with the minimum basis set and a high-level basis set, and also using density functional theory (DFT) density methods with a high level basis set. The agreement hetween theory and experiment for shape of orbital electron momentum distributions is generallygood.