This research provides a innovatively designed mechanism of activating the passivation layer on Fe0 surface as semiconductor to construct a Z-scheme heterojunction in-situ for high-efficiency environmental remediation. Aggregation and passivation of Fe0 and poor visible-light absorption of TiO2 were simultaneously improved by the facile synthesis of a recyclable Fe0@black-TiO2 Z-scheme heterojunction without high-temperature hydrogen atmosphere. The results showed that tetracycline (TC) degradation efficiency with Fe0@black-TiO2 was 1.23 and 2.63 times higher than that of pristine Fe0 and black-TiO2, respectively. The superior degradation arose from strong reduction ability of highly dispersed Fe0 and in-situ constructed Z-scheme heterojunctions. High dispersion of Fe0, construction of the heterojunction, enhanced photodegradability of Fe0@black-TiO2 were systematically elucidated by multiple characterization techniques. Furthermore, photodegradation pathways of TC based on the role of •O2- and •OH were identified. Our results have provided the necessary inspiration and guidance for the development and application prospect of Fe0@black-TiO2 in environmental remediation.