We have investigated the XPS spectra of Ce2Rh3Al9 compound and calculated DOS by using the FP-LAPW (Full Potential Linear Augmented Plane Wave) and TB-LMTO-ASA (Tight Binding Linear Muffin Tin Orbitals) methods. The overall agreement between the calculated and the measured XPS valence band spectra is good. Analysis of the 3d XPS (X-ray Photoemission) spectra, using the Gunnarson-Schonhammer theory, suggests a mixed valence behaviour of Ce. FP-LAPW calculations show a half-metallic behaviour of Ce2Rh3Al9, whereas from LMTO calculations results a semiconducting and nonmagnetic ground state. This result is, however, in contradiction to the resistivity (T) experimental observation, which has not shown an activated behaviour. We attribute a possible appearance of the semiconducting/halfmetallic gap for Ce2Rh3Al9 to an atomic disorder.