The lowpower consumption MCU MSP430F149 is used as the core processor and the PT100 platinum resistance as the sensor, a temperature acquisition system is designed according to the highprecision requirement. To improve the reusability of the system, the precise resistance method is used. It can eliminate the effect on temperature measurement of the drift of constantcurrent source and the precision of reference voltage of A/D circuits. The system design scheme, the standards of constant current source choosing and the current way of deviation elimination, and the operation steps of AD7792 are described in detail. The experiment results show that the measuring accuracy can be up to 0.1 ℃, and comparative tests proved the good stability of the system. The system has been applied to operational service products.