The invention discloses a crack prefabrication device. The crack prefabrication device comprises a plurality of cracked sheets (1), a cracked sheet carrier and a cracked sheet fixing box, the crackedsheet fixing box comprises a horizontally arranged fixing rod (2), the fixing rod (2) is provided with a plurality of through holes (3), slide ways (4) are movably connected at two of the through holes (3), angle fixing buckles (5) are connected between the slide rails (4) and the through holes (3), the slide rails (4) can freely rotate in a left-right direction with the angle fixing buckles (5) as an axis, the cracked sheet carrier is elongated, and is provided with a plurality of cracked sheet fixing buckles (6), the number of the cracked sheet fixing buckles (6) is same to the number of thethrough holes (3), and the cracked sheets (1) are movably connected to the cracked sheet fixing buckles (6). The crack prefabrication device has the advantages of simple structure, low cost and simplicity in operation.