Tendons have a special makeup and set of physiological characteristics that make it difficult for them to mend themselves after damage. Aged tendons are more prone to injury, and wounded tendons will also age faster than usual. This creates a vicious cycle that might cause an injured tendon to reach surgery standards earlier than necessary or cause a re-injury after surgery. Nowadays, the utilization of appropriate medications and exercise is the mainstay of tendon aging treatment. Due to their high potential for differentiation, tendon stem/progenitor cells (TSPCs) have drawn the attention of an increasing number of studies. The mechanism of tendon aging is outlined in this review, along with how it is caused by oxidative stress, hyperglycemia, inflammation, cell apoptosis, fatty infiltration, and its relationship to TSPCs. The goal of this review was to investigate the mechanism of aging and identify related treatment strategies that can effectively prevent further deterioration, slow down tendon aging, and minimize the risk of tendon re-injury following surgery.