A planetary gear assembly for a drum washing machine, comprising: a planetary gear component, comprising: a planet carrier; a plurality of planetary gears rotatably mounted to the planet carrier respectively, a main shaft comprising an outer peripheral wall, wherein the outer peripheral wall is provided with meshing teeth, wherein the plurality of planetary gears are meshed with the meshing teeth respectively, the main shaft being configured to drive a drum to rotate in the drum washing machine; and a planetary gear outer teeth casing fitted over an outer side of the plurality of planetary gears, meshed with the plurality of planetary gears respectively, and configured to be in transmission connection with an agitator in the drum; the planetary gear assembly further comprising a planetary gear casing, wherein the planetary gear component is provided in the planetary gear casing, and the planetary gear outer teeth casing is in transmission connection with the agitator via the planetary gear casing; characterised in that an inner peripheral surface of the planet carrier is provided with meshing teeth meshing with a second shaft in the main shaft; the planetary gear assembly further comprising a second shaft end bearing, wherein the planetary gear casing is provided with a through hole, the second shaft passes through the through hole, and the second shaft end bearing is provided in the through hole and configured to support the second shaft; and a shaft sealing member located in the through hole and at an outer side of the second shaft end bearing, and configured to seal a gap between the second shaft and the planetary gear casing. a planetary gear component, comprising: a planet carrier; a plurality of planetary gears rotatably mounted to the planet carrier respectively, a main shaft comprising an outer peripheral wall, wherein the outer peripheral wall is provided with meshing teeth, wherein the plurality of planetary gears are meshed with the meshing teeth respectively, the main shaft being configured to drive a drum to rotate in the drum washing machine; and a planetary gear outer teeth casing fitted over an outer side of the plurality of planetary gears, meshed with the plurality of planetary gears respectively, and configured to be in transmission connection with an agitator in the drum; the planetary gear assembly further comprising a planetary gear casing, wherein the planetary gear component is provided in the planetary gear casing, and the planetary gear outer teeth casing is in transmission connection with the agitator via the planetary gear casing; a planet carrier; a plurality of planetary gears rotatably mounted to the planet carrier respectively, a main shaft comprising an outer peripheral wall, wherein the outer peripheral wall is provided with meshing teeth, wherein the plurality of planetary gears are meshed with the meshing teeth respectively, the main shaft being configured to drive a drum to rotate in the drum washing machine; and a planetary gear outer teeth casing fitted over an outer side of the plurality of planetary gears, meshed with the plurality of planetary gears respectively, and configured to be in transmission connection with an agitator in the drum; the planetary gear assembly further comprising a planetary gear casing, wherein the planetary gear component is provided in the planetary gear casing, and the planetary gear outer teeth casing is in transmission connection with the agitator via the planetary gear casing; characterised in that an inner peripheral surface of the planet carrier is provided with meshing teeth meshing with a second shaft in the main shaft; the planetary gear assembly further comprising a second shaft end bearing, wherein the planetary gear casing is provided with a through hole, the second shaft passes through the through hole, and the second shaft end bearing is provided in the through hole and configured to support the second shaft; and a shaft sealing member located in the through hole and at an outer side of the second shaft end bearing, and configured to seal a gap between the second shaft and the planetary gear casing.