The invention discloses a construction bracket and a construction system. The construction system comprises a first frame, a second frame and a third frame, wherein the first frame comprises first upright posts and a first horizontal post; the first upright post is fixedly connected with the second frame; the second frame comprises second upright posts and a second horizontal post; the quantity of the second upright posts is equal to that of the first upright posts and the positions of the second upright posts correspond to the first upright posts; the third frame comprises a frame main body and an extension part; the frame main body comprises a plurality of third horizontal posts; the plurality of third horizontal posts are fixedly connected with one end, far away from the corresponding first upright post, of each second upright posts; the extension part comprises at least two extending horizontal posts and a fixed horizontal post connected with the at least two extending horizontal posts; and the at least two extending horizontal posts are fixedly connected with the third horizontal posts. The construction bracket can be placed on a gallery of a commercial complex and the extension part of the third frame can extend outside towards the direction far away from a building from the gallery; and a worker can construct an exterior wall of the building on the extension part of the third frame.