A high precision and low power digital temperature sensor was presented. An internal parasitic PNP was used to sense the temperature. A 14-bit high precision Σ- ADC was designed to convert the voltage signal, which was generated by the front temperature sensing module, into the digital signal. Then the signal was normalized in digital domain at the final output. Compared with the temperature sensors adopting a traditional SAR ADC core, the proposed digital temperature sensor achieved lower power consumption. This circuit was designed and implemented in a 0.18 μm CMOS technology. The measurement results indicated that the temperature accuracy was ±0.7 ℃(at -55 ℃~125 ℃), and the chip area was 1.2 mm2.