Knee creaking when squatting up may be caused by long-term immobilization, meniscus injury and joint cartilage deformation. 1. Long-term immobilization: when the patient keeps the same posture or movement for a long time, it will lead to creaking sound when squatting up. If there is no pain as well as redness and swelling, treatment is usually not needed and can be improved by appropriate rest and activities. 2. Meniscus injury: when the patient does squatting, the injured meniscus is squeezed and makes a sound, which leads to knee creaking. If the damage is mild, it can be treated by physical therapy, such as hot compresses, and if the damage is severe, meniscus repair surgery should be carried out. 3. Deformation of articular cartilage: degeneration of knee cartilage will cause deformation and fracture of cartilage, which will make the knee cartilage squeezed when squatting, and cause a crisp sound. To deal with this situation, patients can go to the hospital for physical, medication and knee replacement surgery. When the knee creaks when squatting up, it is recommended to go to the hospital to receive a doctor’s diagnosis to clarify the cause of the disease and timely treatment.