The utility model discloses an adjustable concrete terrace construction formwork. L-shaped angle iron, the device comprises a horizontal support plate and a vertical backup plate which are fixed together, a circular hole is formed in the supporting plate in the length direction; a vertical screw rod is sleeved with the round hole, an upper locking screw and a lower locking screw which are arrangedon the vertical screw rod in a sleeving mode are arranged on the upper side and the lower side of the supporting plate respectively, the height of the L-shaped angle iron can be adjusted by adjustingthe upper locking screw and the lower locking screw, the lower portion of the vertical screw rod is in threaded connection with the interior of a sleeve, and the lower portion of the sleeve is fixedinto the foundation ground; a plugging block is arranged between the supporting plate and the foundation ground, and the left side wall of the plugging block is flush with the side wall of the backupplate to form a formwork for pouring the horizon. The pouring device is reasonable in structure, novel, unique and convenient to use, improves engineering quality, effectively solves the problems thatan existing device is poor in stability, low in flatness, troublesome to use and not suitable for repeated pouring, is convenient to apply and popularize, and has huge economic and social benefits.