Tennis elbow is mostly caused by chronic injury to the lateral muscles of the elbow joint due to excessive strain, exertion, labor, and improper force, resulting in swelling, congestion, and edema, which leads to pain and limited activity. Preventive methods include avoiding bad stimuli such as holding heavy objects, not working too hard, not walking with heavy objects for a long time, not doing too much laundry at one time, and preventing strain on the epicondylar muscle fascia. Warm up before exercise and then pull the forearm muscles. When engaging in sports that require forearm activity, learn the correct technical movements to avoid further damage to the lateral elbow muscles.