The invention discloses an inclined-plate sedimentation basin used for sewage treatment. The inclined-plate sedimentation basin comprises a cover plate, a raw water pool and steel wire ropes, whereinthe bottom end of one side of the raw water pool is connected with a water inlet pipe; the other side of the raw water pool is fixedly provided with an inclined-plate sedimentation pool communicatingwith the raw water pool which comprises a curing pool, a charging pool and a coagulation pool; the charging pool is located between the curing pool and the coagulation pool; the water inlet pipe communicates with the coagulation pool; two symmetrical corners of the raw water pool and the inclined-plate sedimentation pool are separately fixedly provided with a motor supporting frame; four motor supporting frames are separately provided with a lifting motor; and one end of each of the four lifting motor is rotatably connected with a coiling drum through a rotating shaft. According to the invention, lifting mechanisms are arranged; each lifting mechanism comprises a lifting motor, a first pulley, a second pulley, one coiling drum and one steel wire rope; through working of the lifting motors,the coiling drums are driven to rotate for coil rolling and steel wire rope releasing; and thus, the cover plate is driven to rise and fall, and metal parts arranged on the cover plate are driven torise and fall.