An easy-to-store tangle-reducing and eccentric load-preventing device having adjustable diameter and buoyancy for a washing machine, comprising an upper inserter and a lower inserter; the upper inserter comprises an upper inserter peripheral frame (3), left and right mesh nylon (4) being provided in the upper inserter peripheral frame (3), and an upper inserter notch (5) which opens downwards being provided on the upper inserter peripheral frame (3) between the left and right mesh nylon (4), a row of positioning holes (1) for adjustable separators of the upper inserter being provided on an upper edge of the upper inserter so as to fix the adjustable separators, a hollow expanded portion (2, 6) being provided in the middle part of the upper inserter peripheral frame (3), the inner hollow chamber being a water filling chamber, and a water filling opening (8) being provided on the top of the water filling chamber, the buoyancy being adjusted by filling water, so as to reduce the friction with the agitator of the washing machine; the upper inserter being in inserted connection with the lower inserter by means of the upper and lower inserter notches (5, 10) so as to form a cross-shaped combination. The described easy-to-store tangle-reducing and eccentric load-preventing device having adjustable diameter and buoyancy for a washing machine is effective for preventing eccentric load, is easy to store, and has adjustable diameter and buoyancy.