The invention discloses a frame body and method for improving the coarse adjustment precision of a track skeleton frame of a ballastless track bed and provides the frame body and method for improving the mounting efficiency of the track skeleton frame. The frame body comprises two oppositely-arranged supporting legs, a crossbeam with the two ends being connected with the two supporting legs correspondingly, supporting rods detachably connected to the outer sides of the supporting legs, transverse adjusting bolts used for transversely pulling the crossbeam and being connected with the supporting legs and vertical adjusting bolts used for vertically pulling the crossbeam and being connected to the upper ends of the supporting legs. Vertical guiding grooves allowing the ends of the crossbeam to stretch into are formed in the opposite sides of the two supporting legs correspondingly; vertical adjusting holes allowing the transverse adjusting bolts to penetrate through are formed in the other sides of the two supporting legs; transverse adjusting holes allowing the vertical adjusting bolts to penetrate through are formed in the upper ends of the two supporting legs correspondingly; a groove is formed in the upper end of the crossbeam; and 1:40 transverse slope sections with high outer sides and low inner sides are arranged at the two ends of the groove. The frame body can greatly improve the coarse paving precision of the track skeleton frame.