An adjustable workpiece support system includes an adjustable support apparatus, an analysis support point module, a coordinate post-processing module and a control module. The adjustable support apparatus has a group of support devices for supporting a supported workpiece, the each support device being adjustable in height and angle. The analysis support point module is used to import a computer-aided design file of the supported workpiece, and analyze the computer-aided design file to obtain a group of support points of the supported workpiece. The coordinate post-processing module is configured to calculate the support coordinates of the each support device corresponding to the group of support points. The control module is configured to receive the support coordinates of the each support device, and adjust the height and angle of the each support device to support the supported workpiece, so that the amount of deformation of the supported workpiece is the minimum.