The wireless liquid level transmitter is a smart detection instrument with an integrated design. The product adopts a low power design, and uses a silicon pressure resistant liquid level sensor with stainless steel isolation membrane as the liquid level signal measurement element. The liquid level signal is collected by a high-precision AD converter, and the zero point and temperature performance compensation of the liquid level is realized in a wide temperature range. The product is powered by a quickly replaceable large-capacity long-life lithium thionyl chloride battery pack, and is suitable for outdoor or non-city power supply applications, such as fire water tank, estuary, rain mouth, manhole and other liquid level monitoring; the device uses NB-IoT wireless communication. The data is remotely transmitted to the backend management platform to realize real-time monitoring, alarm processing, statistical analysis and other functions of the field liquid level data.