The invention provides a sample clamping device used for laser punching. The sample clamping device comprises a clamping seat and an elastic device. The clamping seat comprises a containing frame and a clamping plate, wherein the containing frame is of a hollow structure to contain a sample, and the clamping plate is mounted in the containing frame to movably clamp the sample. The elastic device is mounted in the containing frame to apply clamping force for clamping the sample to the clamping plate. The round sample can be clamped firmly and effectively through the clamping plate capable of being opened and closed, by utilizing the elastic device, the sample can be clamped automatically, and clamping structures are reduced. The clamping device does not shield the effective machining area of the sample, and the material utilization rate and the machining efficiency in laser punching can be improved greatly.