Abstract： Objective To investigate the accuracy and utility of preoperative CTA in the anterolateral thigh perforator flap (ALTPF) transplantation.Methods Preoperative CTA was performed in 15 consecutive patients,who underwent the ALTPF transplantation. The suitable perforators were found through measuring and estimating the perforator parameters including size,course and origin location by reviewing preoperative angiogram.These parameters were compared with the actual intraoperative findings.Results One patient was transferred to abdominal flap transplantation,because no perforator could be found by both CTA and intraoperative observation.In 14 patients,the sizes and origin locations ( perpendicular and horizontal length from the origin of the perforator to both patella and lateral of thigh) of all selected perforators on CTA were no significantly different from the operative findings( P ＞ 0.05 ),and the types were consistent with the operative findings.The rate of septocutaneous perforator was 28.6％ (4/14),and the rate of musculocutaneous perforator was 71.4％ (10/14).The utilization rate of perforator flap was 93.3％ ( 14/15),and the accuracy of preoperative CTA was 100％.All of these ALTP flaps survived,and there was no donor site morbidity. Conclusions Preoperative mapping using CTA provides fairly accurate information about the size,type (course) and location of the perforators.Preoperative CTA in the ALTPF transplantation is an accurate and useful method and leads to safer and successful operation with optimal outcome.