The invention discloses an inner barrel for a dewatering machine. The inner barrel includes an inner barrel body (1), water outlet holes (2) formed in the inner barrel body (1), a water collection barrel (3) sleeving the inner barrel body (1), and water drainage holes formed in the water collection barrel (3); drainage grooves (5) are formed in the water collection barrel (3); and the drainage grooves (5) matches the drainage holes (4). The inner barrel is reasonable in design, is easy to operate and install, can rapidly drain water, can avoid damage to a motor due to working heat, can reasonably integrate resources, and is suitable for industrial mass production.