The invention discloses a sedimentation improving method for a ballastless track based on rope saw cutting. The method comprises the following steps that (1) the sedimentation volume of the part, in asedimentation section, of the ballastless track is determined, and the two ends of the sedimentation section of the ballastless track are subjected to bar planting and anchoring; (2) a rope saw operation hole is drilled in the side surface of the ballastless track; (3) a rope saw is adopted for cutting concrete of the ballastless track, bonding constraint of the ballastless track is removed, andthe ballastless track after cutting is limited; (4) a jacking device placing groove is formed in concrete below a horizontal cutting seam; (5) after a jacking system is adopted for jacking the ballastless track to a design value, gaps of the lower portion of the ballastless track after jacking are filled with a filling material to be full, and the line stability recovers; (6) the ballastless trackin the improving area is subjected to bar planting and anchoring, the fastener system is accurately adjusted, and the line smoothness recovers. The method is simple, quick, safe and reliable, in theimproving process, the geometrical state of the ballastless track is stable, the running safety of trains cannot be influenced, and the improving can be conducted in the period of maintaining skylights and is suitable for quick jacking of the ballastless track.