The utility model provides a full-automatic triaxial synchronous straightener for section bars. The technical solution of the utility model is characterized in that: the full-automatic triaxial synchronous straightener for the section bars mainly comprises an X-axis straightener, a Y-axis straightener and a Z-axis straightener; and the three straightener are respectively provided with a detection mechanism and a straightening mechanism. A PLC-controlled closed-loop control system is totally adopted. A PLC-controlled closed-loop system is adopted for the detection mechanism. According to the straightening mode of the X-axis straightener and the Y-axis straightener, pushing and pulling of an operation platform by a hydraulic cylinder for straightening is adopted in the X-axis straightener and the Y-axis straightener. According to a rotation straightening mode of the Z-axis straightener, conversion of push-and-pull movement of the hydraulic cylinder to rotation movement of a rotary head is adopted for straightening the workpiece.