This study aimed to evaluate the nerve regenerative effect and behavior of Schwann cells (SCs) on local administration of autologous platelet‐rich plasma (PRP). Methods Twenty‐eight Japanese white rabbits were used. A 15‐mm sciatic nerve defect was created on the left limb. The resected nerve was used as a reverse autologous nerve. The rabbits were randomly divided into two groups. In group A (n = 10), only nerve grafting was performed. In group B (n = 18), nerve grafting was performed with local PRP administration. Right limbs were used as control (group C, n = 28). The rabbits in each group were equally divided into two subgroups based on the evaluation period of 4 and 12 weeks after grafting. Electrophysiological evaluation, muscle wet‐weight, histological evaluation, and multiple immunofluorescence staining were performed to investigate the regenerative effect of PRP. Results The mean regenerative axon diameter of the graft portion in group B (2.02 ± 0.22‐μm) was significantly larger than that in group A (1.89 ± 0.16‐μm) at 4 weeks. The regenerative axon number at the distal portion showed a greater increase in group B (9017 ± 2224/mm2) than in group A (4955 ± 3117/mm2) at 12 weeks. Electrophysiological evaluation and muscle wet‐weight revealed no significant differences. On immunohistological evaluation, the number of activated SCs increased to a larger extent in group B (188 ± 90/mm2) than in group A (117 ± 51/mm2). Conclusions Local PRP administration increases the regenerative axon diameter and the regenerative axon number at the distal portion. PRP accelerates SC proliferation in vivo.