A split type auto -lock buckle device that is used for fixation formula steel bar truss building carrier plate is including buckle base (1), approximately close in auto -lock top cap (2) of buckle base both sides top surface respectively, join in marriage torsional shear screw (3) of dress on the buckle base, half A circular base recess (1a) has been seted up in the both sides of base top surfacesymmetry to buckle base formula rectangle seat as an organic whole, is provided with crab -bolt (1b) on the both sides of every base recess, the auto -lock top cap be with the rectangle of buckle baselooks adaptation lid, set up the semi -circle top lid recess (2a) right with the base groove phase in every auto -lock top cap bottom surface, set up blocking of both sides wall belt hook teeth (2c)on top cap recess both sides and link up groove (2b) in the crab -bolt, the torsional shear screw is from upwards twisting buckle base middle part down. The utility model discloses it dismantles withend form setting to be convenient for steel bar truss, install of high qualityly, and safe and reliable is just with low costs.