A heat transfer model for low-frequency oscillation laser welding of 7075-T6 aluminum alloy was established. Then, the welding temperature field was obtained by means of numerical simulation. The effects of such welding parameters as laser oscillation frequency, oscillation amplitude, laser power and welding speed on the temperature fields both for conventional laser welding and for oscillation laser welding were studied and compared. The results showed that in conventional laser welding, the temperature field is totally symmetric, the welding temperature rises continuously; however, in oscillation laser welding, the temperature field is asymmetric, and the welding temperature goes up and then down for several times until it reaches the steady state. At the same laser power and welding speed, both the peak melting pool temperature and the heating rate for oscillation laser welding are lower than those for conventional laser welding. In low-frequency oscillation laser welding, the heating rate increases with the increasing of laser oscillation frequency and oscillation amplitude. As oscillation amplitude increases, the peak melting pool temperature decreases, and the width of the melting pool increases.