Objective To explore the clinical effect of using small needle knife in autologous fat grafting for the treatment of atrophic scar.Methods Twelve patients with atrophic scar were included in this study during March 2014 and December 2016 in the Hangzhou First People's Hospital,Zhejiang University School of Medicine.We used small needle knife during fat grafting to treat the atrophic scar.Observer Scar Assessment Scale (POSAS) was used to assess the clinical effect of the patients.Results Aesthetic and functional improvements were observed.Resolution of pain and increases in scar elasticity were objectively assessable.Improvement of both clinical evaluation and patient perception was obtained.Conclusions Use of small needle knife during fat grafting is a good alternative for the treatment of atrophic scars.