Abstract: TC4 titanium alloy samples were printed by using selective laser melting technology（SLM）, and the influence of different forming process parameters（scanning speed, laser power and scanning distance） on the microstructure and corrosion resistance of printed TC4 was studied. The results show that the structure of printed TC4 consists of fine β columnar crystal and a large amount of needle-shaped α martensite.The printed TC4 titanium alloy has higher hardness than the traditional rolled TC4. Its corrosion resistance is mainly affected by the scanning speed. The higher the scanning speed, the worse the corrosion resistance. The surface morphology after corrosion is pitting. The occluded battery is formed between the sample and the corrosion medium, which causes acidification in the corrosion hole, accelerates metal corrosion and makes the corrosion hole continue to develop deeper.