The temperature transmitter uses thermocouples and thermistors as temperature measuring elements. The output signal from the temperature measuring element is sent to the transmitter module, and after being processed by circuits such as voltage stabilization filtering, operational amplification, nonlinear correction, V/I conversion, constant current and reverse protection, it is converted into a 4-20mA current signal of 0-5V/0-10V voltage signal that is linearly related to temperature, and RS485 digital signal output.