The integrated temperature and pressure transmitter is upgraded from GCT15PT product to further improve its low power consumption characteristics. The RS485 interface and power input port are upgraded to make it more suitable for applications in complex field environments. The transmitter can simultaneously measure temperature and pressure signals and output corresponding information through RS485. It supports various types of pressure cores and flexible excitation mode (constant current). Temperature measurement is realized through PT100/PT1000. The measured data is uploaded through RS485, and the whole board circuit is developed according to the requirements of industrial field environment, with high reliability and flexibility. It can be applied to Internet of things products, water resources detection and chemical industry.