Conventional automatic weather stations depend on the electricity and communications infrastructure strongly and the application environment is also restricted. The meteorological observation node based on a wireless sensor network is designed and implemented. The hardware system of weather observation nodes uses the CC2530 chip as the core and lithium batteries as supply power, and connects meteorological sensors via analog and digital interfaces and works on 2.4 GHz. The software system is based on the TinyOS operating system, and various kinds of meteorological sensor drivers and a multihop routing protocol based on LEPS protocol are developed. A test is conducted in field environment, including power, communication distance, sensors, and network performance. Test results show that the meteorological observation nodes form a stable multihop selforganizing data collection and transmission network in the environment without electricity and communications infrastructure. Therefore, it is suitable for deployment and application in the difficult areas such as high mountains, islands and deserts.