A method for using an unbalanced-load and tangling preventer for pulsator washing machines of different drum diameters. Four space dividers (1) are provided in the circumferential direction on a space divider fixing column (4). The lower edges of the space dividers (1) are arcs matching an outer arc of the bottom part of a washing drum. Water guiding holes (2) are provided on the space dividers (1). The water guiding holes (2) are rectangular holes distributed on the space dividers (1) so as to allow a washing liquid to flow among divided spaces of the washing drum. A handle (3) is provided at the upper extremity of the space divider fixing column (4).One movable divider (6) is sleeved respectively on each space divider (1). Provided on the space dividers (1) at the upper edges of the dividers are separator engaging grooves (5) for the placement of engaging pins used for fixing the positions of the movable dividers (6). The present method prevents laundry from deformation or even damage due to excessive tangling, reduces imbalance for a pusator washing machine during a spin-drying rotation process, and is specifically applicable in pulsator washing machines having washing drums of different diameters.