Objective To explore the influence of positioning of the femoral tunnel for medial patellofemoral ligamentre (MPFL)construction on the isometric characteristics of grafts.Method Knee specimens from ten fresh frozen cadavers were used. The attachment of medial patellofemoral ligament was observed. The distance between points from the adductor tubercle, the medial femoral epicondyle, and proximal, distal and central point of the MPFL’s femoral attachment site respectively to the middle point of its patellar attachment site were measured. Changes in length were recorded while the knee was measured by angles of knee flexion (0°, 30°, 60°, 90°, and 120°). Results The length changes in every point were compared. All of the maximal length changes of its adductor tubercle: proximal points were not greater than 3 mm. There was no significant difference between the length changes of adductor tubercle and proximal points（P>0.05）. Conclusions The position of the femoral turnel for MPFL reconstruction should be located as follows: MPFL should be at the middle point of upper edge of femoral attachment site (proximal point), and the point can appropriately be shifted to adductor tubercle.