The utility model discloses a three-side indented wire for middle-strength pre-stress concrete. The three-side indented wire comprises a steel wire body and three indented strips, wherein the diameter of the base circle of the steel wire body is 3.85-11.78 mm; the three indented strips are uniformly arrayed along the circumferential direction of the steel wire body and each indented strip is composed of a plurality of single indented bodies which are arrayed along the axial direction of the steel wire body at intervals; and the depth of each indented body is 0.07-0.27 mm, the length of each indented body is 3-5.5 mm and the pitch of the indented bodies in each indented strip is 5-8.5 mm. The three-side indented wire for the middle-strength pre-stress concrete is high in tensile strength, and cracks or breakage can not be generated after the three-side indented wire is bent for multiple times.