Objective: To investigate the side effects of 585nm pulsed dye laser in treatment of the vascular abnormalities. Methods: We analysed the side effects of 500 cases treated by 585nm pulse dye laser. Results: There were 89 cases occuring side effects in 500 cases patients, pigmentation 35 cases, pigment droping 12 cases,atrophic scar 40 cases, hyperplastic scar 2 cases. Occuring of side effects have nothing to do with the types of disease and the energy of treatment, It is relevant to frequency of treatment. Conclusion; The 585nm pulsed dye laser haven't side effects of hyperplastic scar and continued pigmentation treated by continuous lasers, It's safe in treating vascular abnormalities.