Research purposes: To explore the clinical effect of local injection of autologous platelet-rich plasma (platelet-rich plasma) for lateral epicondylitis of humerus. Research method: A total of 58 patients with lateral epicondylitis of the humerus who were treated in the orthopedics department of our hospital from January 2018 to December 2018 were selected and included in the study. Subjects were treated with local injection of autologous platelet-rich plasma. Before the treatment, at 1 week, 1 month and 3 months after the treatment, the subjects were evaluated with visual analogue scale (VAS) and Mayo elbow function score (MEPS) for pain and elbow function. Results: Compared with before treatment, VAS decreased and MEPS increased after treatment. The four indicators of MEPS—pain, activity, stability, and daily abilities were significantly improved. Conclusion: Local injection of autologous PRP in the treatment of lateral epicondylitis of the humerus can better relieve pain symptoms and improve elbow joint function.