The maintenance time of hyaluronic acid injection varies depending on the patient’s body type, the type of hyaluronic acid, and the number of injections, and can generally last from three months to two years. Hyaluronic acid injection has the advantages of quick effect, small invasion and low risk, but the maintenance time will not be very long. Firstly, if the patient has a strong absorption capacity, the maintenance time is usually shorter, and vice versa, the maintenance time is longer. Secondly, the maintenance time varies depending on the type of hyaluronic acid. Large molecule hyaluronic acid usually has a longer maintenance time of about one to one and a half years, while the maintenance time of small molecule hyaluronic acid is usually about six months. In addition, the initial injection of hyaluronic acid has a shorter maintenance time, while the second and subsequent injections will have a longer maintenance time. It should be noted that the injection of hyaluronic acid must be carried out by the plastic surgery department or dermatology department of a regular hospital to avoid bringing troubles to the appearance. In addition, pay attention to rest after hyaluronic acid injection, and do not touch the injection site with force in the short term.