In order to obtain the influence of barrel parameters on the laser-driven flyer velocity and morphology, the velocities and evolution process of laser-driven Al flyers confined by steel barrels with various diameters and lengths were investigated using Photonic Doppler Velocimetry (PDV) and Shadowgraph technique. The maximum velocity of 3100 m·s^-1 can be obtained when the diameter of the barrel was 800 μm, which is equal to the size of the Al flyer ablated by laser. When the diameter of the barrel was larger than 800 μm, it can not restrain the flyer effectively, and the velocity of the flyer decreased, which led to the lowest velocity of 2700 m·s^-1 with the barrel’s diameter of 1500 μm. When the diameter of the barrel was 600 μm, the energy around the flyer was wasted and the velocity of the flyer decreased to 2900 m·s^-1. The results also showed that flyer velocity decreased with the increase of the barrel length. Shadowgraph results showed that the Al flyer was fragmented and splashed around after it got away from the barrel exit, indicating that it was difficult for a 20 μm Al foil to maintain integral and planar when ablated by a pulsed laser.