U-SIN-P260S/P261S/PX261S-CN2 immersion liquid level transmitter is composed of high-performance diffused silicon piezoresistive pressure sensor as the measuring element, the liquid static pressure which is proportional to the liquid level depth is accurately measured, and converted into standard (current or voltage) signal output through signal conditioning circuit, and the linear correspondence relationship between output signal and liquid level depth is established, realizing the measurement of liquid level depth. The product has high accuracy and small volume, and can measure the liquid height from the end of the transmitter to the liquid surface by directly immersing it in the liquid, which is convenient to use. It is suitable for liquid level measurement and control in petroleum, chemical, power plant, urban water supply, and hydrogeological exploration.