In order to accurately measure the temperature, it can be taken platinum res istance (Pt100) as a sensor of temperature measurement device, but it brings about the temperatureresistance nonlinear characteri stics. A unique precise algorithm for the conversion of platinum resistance nonl inear signals into air temperature is put forward by introducing platinum resist ance characteristics, and it is also the software table look up law and the method of average which carry out the two levels of error adjustm ents. The realization of this unique algorithm consists of the hardware and soft w are parts. The hardware is based on the good performance of A/D co n verter for the core component of the selfcalibration and system ca libration features in the precision conversion circuit, and the software is give n by the principa l source code, to achieve precision temperature measurement. The method is well applied in the temperature measurement devices.