A water supply-replenish control method of a multi-drum washing machine, said multi-drum washing machine comprising a first washing drum and a second washing drum and a controlling unit, wherein during a washing process of the first washing drum, if a water level of washing water is lower than a set value, a water replenishment process is executed, the controlling unit determines whether or not the second washing drum is controlled to be executing a water replenishment process before the water replenishment process is executed in the first washing drum, if yes, the controlling unit controls the first washing drum to pause executing the water replenishment process, the second washing drum is controlled to continue executing the water replenishment process; if no, the controlling unit controls the first washing drum to execute the water replenishment process, and terminate the water replenishment process after the water level of the washing water reaches the set value, wherein, the controlling unit determines whether or not the second washing drum is about to execute or executing a drainage process before the first washing drum is controlled to execute the water supply process or the water replenishment process; if no, the controlling unit controls the first washing drum to execute the water supply process or the water replenishment process; if yes, the controlling unit determines whether or not washing water in the second washing drum is reused; if yes, the first washing drum is controlled to pause executing the water supply process or the water replenishment process, and the washing water in the second washing drum is controlled to flow into the first washing drum as water resource for water supply or replenishment when the second washing drum is controlled to start to drain, wherein, a determination condition of whether or not the second washing drum is about to be controlled to execute the drainage process is whether or not a remaining time for the second washing drum executing a next drainage process is shorter than a set time. wherein during a washing process of the first washing drum, if a water level of washing water is lower than a set value, a water replenishment process is executed, the controlling unit determines whether or not the second washing drum is controlled to be executing a water replenishment process before the water replenishment process is executed in the first washing drum, if yes, the controlling unit controls the first washing drum to pause executing the water replenishment process, the second washing drum is controlled to continue executing the water replenishment process; if no, the controlling unit controls the first washing drum to execute the water replenishment process, and terminate the water replenishment process after the water level of the washing water reaches the set value, wherein, the controlling unit determines whether or not the second washing drum is about to execute or executing a drainage process before the first washing drum is controlled to execute the water supply process or the water replenishment process; if no, the controlling unit controls the first washing drum to execute the water supply process or the water replenishment process; if yes, the controlling unit determines whether or not washing water in the second washing drum is reused; if yes, the first washing drum is controlled to pause executing the water supply process or the water replenishment process, and the washing water in the second washing drum is controlled to flow into the first washing drum as water resource for water supply or replenishment when the second washing drum is controlled to start to drain, wherein, a determination condition of whether or not the second washing drum is about to be controlled to execute the drainage process is whether or not a remaining time for the second washing drum executing a next drainage process is shorter than a set time.