The paper introduced a low-power wireless pressure transmitter for measure pressure and temperature of oil-well. To avoid wiring cables onsite, ZICM2410 was adopted to construct Wireless Sensor Network (WSN), and powered by Li-Ion battery. To reduce the power consumption, MSP430F477 and other low-power chips were used to construct the hardware, and energy conservation strategies were designed in the software. One strategy was turning off the power when some chips or modules were not on duty. Another strategy was working, sleeping and timer waking up. The SNAP wireless network solution of Zigbee was used to compose WSN. By analysis and test, the power consumption of the transmitter is very low, and the transmission range of it could be up to 300m. It could longtime continuously work for the low power consumption ability. The transmitter could fully meet the actual requirements, and could be applied to other industry situations easily.