Background: This study was aimed to investigate the distribution of Internal mammary artery perforator for flap design by digital subtraction angiography and metal pins on the chest before operation. Methods: 32 participants were randomly collected in observation. The distributions of the IMAPs were assessed by either selective DSA combining the metal pins on the chest as experimental group, or ultrasonic examination as control group before surgery and the anatomical data were recorded. 22 were assessed using DSA while 10 ultrasound. The island flap was harvested according to the marked traces. Results: All 44 sides of IMAP distributions detected by DSA were displayed clearly while 12 ultrasound imagings of 20 cases showed only the starting point of IMAP. Of the DSA imagings, the largest IMAP was documented to be in the second (36/44), third (7/44) intercostal space and 4th (1/44) intercostal space. The average length of visible IMAPs was 5.72 +/- 1.20 cm on the right side and 5.70 +/- 1.16 cm on the left side, and the average caliber was 1.37 +/- 0.23 mm and 1.35 +/- 0.22 mm respectively. The ascending, descending and irregular type of IMAP distributions respectively accounted for 3/44, 38/44 and 3/44. The mean angle between the horizontal line and IMAP stems was 5.2 degrees and 13.4 degrees respectively in the ascending and descending type. Conclusions: DSA combining with metal pins on the chest offers a vascular distribution of IMAP before operation and greatly improves the safety of the IMAP.