Water level detection method of roller washing machine and roller washing machine

The invention relates to a water level detection method of a roller washing machine and the roller washing machine, and the method comprises the steps that when the roller washing machine rotates at a preset rotating speed, a first signal fed back by a sensor is acquired, and the sensor is arranged at the position of a cylinder opening of the outer wall of an inner cylinder of the roller washing machine; the first signal represents time information when the sensor is just in contact with liquid in the roller washing machine; a second signal fed back by the sensor is obtained, and the second signal represents time information when the sensor leaves the liquid; the water level height value of the roller washing machine is determined based on the first signal, the second signal and the preset rotating speed, and the duration, determined through the first signal and the second signal, of the sensor making contact with the liquid has a preset corresponding relation with the preset rotating speed and the water leve