To investigate the influence of laser power and scanning path spacing on the height of microstructures formed by the scanning laser shock forming process，this paper employs nanosecond fiber laser to form micro protrusions array with diameter of 200 μm on aluminum foil with thickness of 20 μm by Laser shock forming. The three-dimensional morphology of micro protrusionsis measured by using a laser confocal microscope. The results indicate that during the process of laser power changing from 10 W to 18 W，the height of the formed microstructure increases from 17 μm first to 29 μm and then decreases to 12 μm. When the scanning line spacing changes from 30 μm to 50 μm，the height of the formed microstructure increases gradually from 14 μm to 30 μm. The influence of laser power and scanning line spacing in the scanning laser shock forming process is essentially the common result of the constraint of the energy absorption layerthickness and the influence of the strength of the shock wave generated by laser ablation of the energy absorption layer. This comprehensive influence needs to be paid attention to in the multi pass scanning laser shock forming.