A mounting pin straightness management system is provided. The system includes a sensor unit that is configured to measure 3-dimensional coordinates (a(Ta, La, Ha), b(Tb, Lb. Hb)) for a first and a second center point (a, b) of two approximate circles formed from intersections of an exterior surface of the at least one mounting pin and two parallel planes (PA and PB) perpendicular to a target length direction of the at least one mounting pin and spaced apart at a predetermined distance (H) from each other. A controller is configured to calculate a straightness index (S.I.) related to a maximum distance (Lmax) between the first and the second center point under a straightness management tolerance (r) and an actual distance (Lactual) between the first and the second center point by receiving the 3-dimensional coordinates of the first and the second center point from the sensor unit.