The invention relates to a liquid-level monitoring system for a ship fire-control high-pressure sealed fire extinguishing agent container. Particularly, a detection device is capable of detecting whether the fire extinguishing agent container has the normal fire extinguishing capacity or not by periodically monitoring the liquid level of the fire extinguishing agent container, and meanwhile has the real-time liquid-level measurement and data uploading function. The liquid-level monitoring system is composed of a power monitoring module, a control module, a driving module, a signal processing module, an ultrasonic sensor and a wireless module. According to the liquid-level monitoring system for the ship fire-control high-pressure sealed fire extinguishing agent container, the liquid level of the ship high-pressure sealed fire extinguishing agent container can be periodically monitored, liquid-level data is uploaded to a fire extinguishing control system in real time through the wirelessmodule, and meanwhile the liquid-level monitoring system has the function of measuring the liquid level of a fire extinguishing agent in real time through a Bluetooth communication module. The liquid-level monitoring system for the ship fire-control high-pressure sealed fire extinguishing agent container has the advantages that the function of the fire extinguishing control system is expanded, the control level and reliability of the system are improved, the liquid-level monitoring system has the real-time measurement function, sailors can irregularly carry out spot checks and detect the liquid level, and the ship fire-control safety is further guaranteed.