The disclosure provides a liquid taking device and a liquid taking method. The liquid taking device comprises a liquid taking bottle, a heavy ball and liquid taking ropes. The liquid taking bottle has a first mouth and a bottom opposite to the first mouth. The heavy ball is arranged in the liquid taking bottle. The liquid taking device can be controlled to reach different depths under the ground by the action of two liquid ropes. When the first mouth of the bottle is placed facing downward, the heavy ball blocks the first mouth of the bottle under its own gravity to prevent liquid leakage; when the first mouth of the bottle is turned upwards under the action of the liquid taking rope, the heavy ball falls onto the bottom of the bottle, such that an external liquid can flow into the liquid taking device, which has a good practical utility.