Electron emission from multiwall carbon nanotube film induced by the irradiation of the second, third and fourth harmonics of a Q-switched Nd:YAG laser was studied as a function of applied voltage and irradiation energy. The experimental result at 266 nm showed a one-photon field-assisted photoemission mechanism at low laser energy and a thermal contribution at higher energy. At 355 and 532 nm wavelengths, the emission seems to be due to thermal assisted field emission.