OBJECTIVE: To study the histocompatibility and degradation in vivo of a new artificial material, calcium polyphosphate fiber (CPPF), and to provide some experimental basis for further study in tendon tissue engineering. METHODS: CPPF and carbon fiber (CF) as control material were implanted in symmetry part in subcutaneous layer, muscle and Achilles tendon of 20 SD rats. The day of operation, the 4th, 8th, 12th, 16th, and 20th weeks after operation, X-ray examination was performed to detect the density change of materials. Local tissue and materials were observed grossly, and pathological examination was made with HE staining 4, 8, 12, 16 weeks after operation. RESULTS: CPPF degraded completely within 16 weeks in muscle, and in 20 weeks after implantation in Achilles tendon and subcutaneous layer according to X-ray and pathological examination. No calcium phosphate crystal deposit was observed in local tissue. No obviously degradation of CF was found within 20 weeks. Local infiltration of lymphocytes and macrophagocytes around CPPF were much fewer than that of CF. CPPF combined compactly with surrounding hyperplastic tissue. CONCLUSION: CPPF degrade thoroughly from 16 to 20 weeks without sediment of crystal of calcium phosphate in vivo. CPPF has good histocompatibility and can be used as a scaffold material of tissue engineering.