The selective laser melted TC4 alloy has been chemical polished in HF–H₂O₂ solutions. The effects of chemical polishing time and H₂O₂ concentration on the surface morphology, roughness, gloss, weight loss rate and thinning rate of the specimens during chemical polishing have been investigated. The result shows that the surface roughness of the specimen gradually decreases, while the gloss, the weight loss rate and the thinning rate of the specimen  increase with the increase of chemical polishing time; and with the increase of H₂O₂ concentration, the surface roughness of the specimen firstly decreases and then increases, while the gloss, the weight loss rate and the thinning rate firstly increase and then decrease. In particular, the optimal chemical polished surface of the specimen has been obtained at the HF：H₂O₂ volume ratio of 1：5, the chemical polishing time of 8 min. After chemical polishing in the above optimal solution, the adhered powders of the specimen have been completely removed, with the surface roughness R_a of (3.5±0.3) μm, and the gloss of (80.3±0.7) GU, and the surface quality of the specimen has been significantly improved compared to that of the asbuilt specimen (surface roughness of (13.3±0.8) μm, and the gloss of (0.9±0.3) GU). Moreover, the chemical polishing mechanism of titanium alloy in HF–H₂O₂ system has been also discussed.