The invention provides a stepping self-walking cantilever timbering of a fully mechanized workface, wherein the stepping self-walking cantilever timbering comprises three parts of a flexible cantilever beam timbering, passing and anti-falling jacks and a stepping self-walking support timbering. The flexible cantilever beam timbering comprises top beams (1), bases (3), front and rear columns (2) and double linkage mechanisms (4) which are arranged at left and right sides of the flexible cantilever beam timbering, and also comprises crossbeams (12), longitudinal beams (11), telescoping beams (10) and telescoping jacks (14) which are disposed at the center of the flexible cantilever beam timbering. The two passing and anti-falling jacks are respectively positioned at the left and right sides of the timbering, wherein two ends of the passing jack (5) are respectively coupled with the bases (3) and bases (6) by fixed connectors and two ends of the anti-falling jack (9) are respectively coupled with the top beams (1) and top beams (8) by rotatable connectors. The stepping self-walking support timbering comprises the top beams (8), columns (7) and the bases (6) arranged at the left and right sides and also comprises a crossbeam (13) disposed at the center. With hydraulic pressure as power, the timbering, which is a piece of mechanized cantilever support equipment used in association with a fully-mechanized excavation machine, realizes the cantilever support and the stepping self-walking of a top board of the fully mechanized workface and mechanizes the temporary support of the fully mechanized workface, enhancing the working efficiency and reducing the danger of manual operation.