Objective Platelet-rich plasma (PRP) secretes many growth factors, including transforming growth factor β1 (TGF-β1), platelet derived growth factor, vascular endothl ial growth factor, insul in-l ike growth factor 1, and so on, which can promote cell prol iferation, chemotaxis, and collagen synthesis in wound heal ing. To investigate the effects of PRPon the tendon heal ing, and to explore the mechanism of action so as to provide the experimental basis for the tissue engineered tendons. Methods Forty healthy New Zealand white rabbits, weighing 2.5-3.0 kg and male or female, were randomly divided into the experimental group (n=20) and the control group (n=20). PRP was prepared from arterial blood of rabbit’s ears through twice centrifugation method of Landesberg. The platelet concentrations of whole blood and PRP were determined. The right achilles tendons of the rabbits were transected to make rupture models. In experimental group, the tendon was sutured after PRP (0.5 mL) was immediately appl ied at repair site. In control group, the tendon was sutured directly after transection. At 1, 2, 4, and 6 weeks after operation, the tendons of 5 rabbits in each group were harvested for morphological, histological, and immunohistochemical observations; the fibroblast counting, the content of collagen fibers, and the expression of TGF-β1 were detected. Results The concentration of platelet of PRP was 4.03 times of whole blood. All the animals survived till the end of the experiment, and the incision healed well. No death, infection, and other compl ications occurred. With time, the tendons almost healed in 2 groups, and the fibrous tissue at anastomosis site was more remarkable in control group than in experimental group. The histological observation showed significant differences in fibroblast counting at 1, 2, and 4 weeks after operation between 2 groups (P lt; 0.05), while no significant difference at 6 weeks (P gt; 0.05). The contents of collagen fibers in the parenchyma at repair site in experimental group were significantly higher than those in control group at each time point (P lt; 0.05). Immunohistochemistry staining showed the expression of TGF-β1 in experimental group was upregulated at 1 week and 2 weeks and reached the peak at the 2nd week, and subsequently downregulated at 4 and 6 weeks in comparison with the control group, showing signficant differences between 2 groups at each time point (P lt; 0.05). Conclusion PRP can facil itate rabbit’ s tendons heal ing and significantly improve the heal ing qual ity, which may be associated with its advancing the peak time of the TGF-β1 expression in tendon.