After the preparation of the multi-feature micro-bending mold, the isobaric micro-bending of foil plate can be achieved by laser dynamic flexible microforming under single pulse. In order to investigate the workpiece size (thickness) and grain size effects on high strain rate deformation behavior of foil plate, the digital microscopic is used to observe the surface topography of formed parts. Besides, Triboindenter nanomechanical test instrument is employed to obtain the micro-hardness distribution along thickness direction. With the aid of cold mosaic technique, the thinning rate of thickness is measured. Experimental results show that the contour of formed parts change from dome shape to groove shape when the thickness decreases from 50 μm to 30 μm due to the reduced flow stress of copper foil. After the strong impact with the bottom of micro-mold, the groove-like parts rebound and the micro-hardness of parts is improved significantly. Compared with the fine-grained formed parts, the forming ability is rather poor with the uneven rebound deformation and strain hardening across thickness direction. The maximum thinning rate of coarse-grained parts has an increase of approximately 10% than the fine-grained ones, which means the fillet region is easier to rupture.