A patellar tendon fixer is used as an orthopedic operation tool which is used for a full-knee-joint displacement surgery and can fix the patellar tendon. Double rows of stereo arc-shaped long nails which form an H-shaped member are used for reinforcing patellar tendon adhesion position. The patellar tendon fixer is obtained through fixing after placing a connecting rod between two arc-shaped double-head long nails. Two heads of each arc-shaped long nail are sharp heads and comprise a long head and a short head. The nail length of the long end is 1.0cm, and the nail length of the short end is 0.6cm. The distance between the two ends is 1.5cm. The length of the middle connecting rod is 1.2cm. The thickness of the connecting rod and the nail is 1.5cm. The patellar tendon fixer is made of high-nitrogen no-nickel stainless steel which has elastic module that is most same with human body and has better biocompatibility. The patellar tendon fixer can protect the patellar tendon when a kneecap is overturned and is placed on a patellar ligament adhesion tibia in the full-knee-joint displacement surgery.