We have deposited a series of orthorhombic TmMnO3 thin films on LaAlO3(LAO)(110) substrates by pulsed laser deposition (PLD) under different oxygen pressures. These samples presumably will allow us to study how the magnetic properties of this multiferroic material vary with any structural variance induced by oxygen. In addition, it is also expected to give important implications in terms of considering device application. Our results show that the films deposited at PO2=0.05 torr appeared to display better crystalline quality and well-defined magnetic structure transition.