With the rapid development of medical science and technology, many diseases have been overcome by medical practitioners, and more and more patients are demanding not only a cure, but increasingly want to obtain effective treatment of complex diseases with minimal pain and trauma. The advantages of endoscopic surgery cater to this desire. Arthroscopic surgery is one of the more mature and versatile of these techniques, with knee arthroscopy being the most versatile, fastest growing and most mature. The following is an overview of knee arthroscopy and its indications for treatment. Knee arthroscopy extends the surgeon’s vision through a specialized optical system. A small incision of less than 1 cm is made around the patient’s knee joint and an arthroscope of only a few millimeters in diameter is placed in. This arthroscope, although small, contains three parts: a lens system, an optical fiber system, and a joint perfusion system. Through the monitor attached to the arthroscope, the doctor can clearly observe the internal structure of the joint and the damage, and make a very accurate diagnosis. Arthroscopy is more accurate than X-rays, CT, or MRI because the diagnosis is almost visual, as the lesion is seen under direct vision. This is only the diagnostic aspect of arthroscopy, but with one or two small incisions and the use of specialized instruments, many procedures can be performed that previously required an incision of the joint. These procedures involve almost all areas of knee surgery. In other words, many knee procedures that were previously performed can be done arthroscopically in the knee. The indications for knee arthroscopy are very broad, such as: synovitis of the knee from various causes (traumatic, rheumatic and rheumatoid, serologically negative arthritis, etc.); fluid and blood accumulation in the knee; osteoarthritis; intra-articular infection in the knee; intra-articular free bodies due to synovial chondromatosis, crystalloid arthritis, etc.; plication or removal of meniscal injuries and deformities of the knee; intra-articular fractures or cartilage due to trauma Injury; synovial crease removal; fat pad removal; habitual patellar dislocation; knee stiffness release; knee cruciate ligament injury repair and reconstruction, etc. In summary, knee arthroscopy performs more complex procedures with very little patient injury. Patients can exercise very early after surgery, preventing joint stiffness and muscle atrophy due to the large surgical injury and the inability to exercise early. This greatly reduces the patient’s pain and shortens the time of treatment.