The invention discloses a metallographical test piece polishing clamp. The metallographical test piece polishing clamp comprises a cross-shaped fixing support module, a protection cover module, a liquid dropping module and a test sample clamping module, wherein the protection cover module, the liquid dropping module and the test sample clamping module are connected with the cross-shaped fixing support module. The metallographical test piece polishing clamp is simple in product structure and convenient to operate, the clamp and devices for fixing the clamp are arranged, the design of a clamping screw enables the clamp to be used more flexibly, the clamping condition of the clamp can be adjusted in time according to the shape sizes and the stress conditions of test samples, and the polishing accuracy is adjusted. According to the product, the multiple test samples can be polished at the same time, the manufacturing efficiency of metallographical samples is improved, other resources do not need to be consumed, and therefore the metallographical polishing process is easy, rapid and convenient. A guide rail support is adopted, and the position of the test sample clamping device can be freely adjusted in the guide rail direction, so that any-position movement of the test samples on a polishing disc is achieved, and the requirement for polishing is met.