The utility model relates to a support adjustable slope device for becoming prefabricated beam bridge of assembling in slope, include: support slope adjusting part, by have ball grooves go up the steel sheet and have spherical convex surface under the steel sheet form, ball grooves is the same with the spherical convex surface radius, closely laminates to form with the rotation that realizes arbitrary direction and indulges or the cross slope degree, support anchor assembly comprises anchor sleeve and crab -bolt, the crab -bolt setting last steel sheet top surface be used for with the pre -buried steel sheet anchor of the roof beam body, pre -buried steel sheet passes through helicitic texture and anchor muffjoint, the anchor sleeve comprises steel sleeve and rubber sleeve, and the inner wall has the draw -in groove, and with the stupefied formation anchor structure of the annular anchor of crab -bolt, the lateral wall has 3 breathing seams, cooperates inserting and the locking of crab -bolt. The utility model provides a support adjustable slope device simple structure, simple to operate, safe and reliable for the prefabricated beam bridge of assembling of variable gradient. It has the beam mold board of leveling steel sheet to need not the preparation when the erection support, saves labour and saves trouble, and the quality is guaranteed easily.