The utility model relates to a safe working platform for enclosing purlins. The device comprises a longitudinal rod (1) and a transverse rod (2), the longitudinal rods (1) and the transverse rods (2)are fixed into a rectangular platform through fixing rods (8). a rectangular steel plate (9) is arranged on the rectangular platform; a purse seine stand column (4) is arranged at each of two ends ofthe front part of the rectangular platform; the purse seine stand column (4) is perpendicular to the rectangular platform. The bottoms of the purse seine stand columns (4) are connected with the rectangular platform in a welded mode. A purse seine (10) is arranged between the two purse seine stand columns (4), the two ends of the rear portion of the rectangular platform are each provided with a vertical rod (3), the middles of the vertical rods (3) are connected with the rectangular platform in a welded mode, adjustable fixing devices (11) are arranged on the upper portions of the vertical rods (3), and two bolt holes (5) are formed in the lower portions of the vertical rods (3). Safety construction of foundation pit engineering is achieved, and operation safety of operators is guaranteedwhen prestress is applied to the steel support.