To exploring fiber laser cutting of aluminum, fiber laser cutting of AA6061 Al alloy with the thickness of 2 mm is carried out. The effects of welding parameters such as laser power, cutting speed and the pressure of assisting gas on the quality of the kerf are investigated. The results show that accepted kerf can be obtained under appropriate parameters. The accepted kerf with the dross height less than 0.1 mm, the surface roughness less than 3 μm, and no megascopic gap as the kerfs are matched. It is found that when the laser power is 3.0 kW, the cutting speed of fiber laser that obtains accpeted kerf can be up to 9 m/min, which is two times than that of CO2 slab laser with the same laser power. Moreover, by increasing laser power to 3.0 kW, enhancing cutting speed rate to 6 m/min, raising stand-off to 0.5 mm, or increasing the pressure of assisting gas to 1.1 MPa, the dross height of the kerf is reduced to less than 0.1 mm. The minimum dross height is only 20 μm. The results show that the surface roughness is around 3 μm, and the minimum width of heat affected zone is 10 μm. Finally, a model is established by linear regression, whose estimated value agrees with experimental data well.