The knee rattles when squatting: 1. It may be a physiological rattling sound, generally caused by the release of gas from the joint fluid within the joint. 2. It may also be due to the knee flexion and extension activities, causing the tendons and bones to rub against each other. 3. 4, there is also the painful symptoms that occur after the meniscus is damaged. So, if the knee rings when you squat, if it’s just once in a while, it’s usually not a big problem. If the frequency of squatting knee ringing is high, and accompanied by pain symptoms, after bed rest, avoid strenuous activities, symptoms do not have any relief, must promptly go to a regular hospital to improve the MRI examination of the knee joint, clear causes after the choice of reasonable treatment, so that a squatting knee ringing symptoms to get timely and effective relief.