An intelligent non-contact liquid level sensor adopts advanced signal processing technology and a high-speed signal processing chip and it won't be influenced by container wall thickness when detecting the liquid level in an airtight container. The liquid level sensor is installed under the container (high level and low level). No need to bore a non-metallic container, easy to install. It can detect liquid levels of various toxic substances, acid, alkali and all kinds of liquid in high-pressure airtight containers. It can be widely used and has no special requirement for liquid medium and material of the container.