The invention discloses a purifying water trough. The purifying water trough comprises a trough body, a plasma generator, a trough body bottom wall, a water pump, a heating pipe and a rotary arm spray nozzle. The trough body is provided with a table top, an opening is formed in the top of the trough body, and the table top is arranged around the opening. The plasma generator is provided with an electrode head and a control part electrically connected with the electrode head, the control part is embedded in the table top, and the electrode head is detachably installed on the table top and can be arranged in the trough body. The trough body bottom wall comprises a water trough bottom plate, a filter screen and a rotary arm seat, wherein the water trough bottom plate, the filter screen and the rotary arm seat are spliced to one another to make the trough body bottom wall roughly flat. The water pump and the heating pipe are both arranged below the trough body bottom wall. The rotary arm spray nozzle is arranged on the rotary arm seat and is in fluid communication with the water pump. The purifying water trough is provided with the plasma generator, and thus the purifying, sterilizing and pesticide residue removing effects can be effectively achieved; the water pump, the heating pipe and the like are arranged on the lower side of the bottom wall, so that the design space for the bottom wall is enlarged, and thus the filter screen and other devices such as ultrasonic vibrators can be conveniently arranged.