A liquid detection system for detecting a liquid level position of a liquid in a hanging bottle includes a hanging bottle casing unit for determining the overall gravity of the hanging bottle, a hanging bottle cap unit for determining the liquid density in the hanging bottle, and a transmission unit for transmitting the overall gravity and liquid density of the hanging bottle to a server, and the server. The server is configured to determine the liquid gravity in the hanging bottle, calculate the liquid volume in the hanging bottle based on the liquid gravity and the liquid density, and determine a liquid level position based on the liquid volume.