The utility model discloses a flatness error detection device for processing scene, including the motor, the shaft coupling, the lead screw, the percentage table, calculate control system, the motor passes through shaft coupling and lead screw hookup, the nut is installed to the screw thread on the lead screw, the vertical fixation has the bracing piece on the nut, nut one side has the benchmark dull and stereotyped, the dull and stereotyped tetrapod of benchmark is supported fixedly respectively by a jack, the cover is equipped with a portable fixed block and fixed through a locking screw locking on the bracing piece, one side of portable fixed block is fixed with the fixed column, fixed column middle part trompil runs through a regulation pole and passes through two lockings of locking screw, the front end of adjusting the pole stretches to the dull and stereotyped top of benchmark and the front end tip is fixed with the fixing base through three lockings of locking screw, be fixed with the measuring staff through four lockings of locking screw on the fixing base, on the measuring staff, the lower extreme is the fixed connection percentage table respectively, the gauge head, the signal output part and the computer control system of percentage table are connected. The utility model discloses measure simply, efficient.