OBJECTIVE: To observe the revascularization and the opportunity of cross-finger flap. METHODS: An animal model was developed to permit daily monit oring of neovascularization of the flap with autoradiography, tissue transparent technique, gross observation and histological examination. RESULTS: The revascularization of the flap was chiefly raised f rom the surrounding tissues. The pedicles of 334 cross-finger flaps of the pati ents were successfully divided from 1 to 5 d after operations, averagely 3. 3 d. All of the cases showed satisfatory results according to a follow-up sur vey of 3 to 72 mon. The results further proved that the revascularization of the cross-finger flaps had accomplished within 3 d. CONCLUSIONS: It suggests that the division of a cross-finger f lap can be carried out between the 3rd and 5th day after operation with a high d egree of safety.