The present invention relates to a device in the technical field of material processing, in particular to a peener which carries out the surface deformation strengthening process on magnesium alloy samples. The present invention comprises a main peening system, an upper whirlwind separation system, a dedusting system, an air compression system and an electric system, wherein, the upper whirlwind separation system is positioned on the upper end of the main peening system, the lower part of the upper whirlwind separation system is communicated with the main peening system, the upper part is connected with the dedusting system, which is positioned outside the main peening system, the air inlets of both the dedusting system and the main peening system are connected with the air compression system, and the electric system is connected with the main peening system, the upper whirlwind separation system, the dedusting system and the air compression system. The present invention can conveniently assemble and disassemble the samples of the shaft class, the range of the generated peening strenghth is wide, the effect and uniformity of peening is good, and moreover, pollution can be prevented.