Abstract: The wireless sensor network technology based on ZigBee protocol was researched. Some wireless network sensor nodes and a sink node based on embedded technology were designed. The nodes which acquired soil moisture information, were regularly distributed in the monitoring area. The sink node collected the information of nodes and implemented dynamic display of information and large-capacity storage. With these wireless sensor nodes, the factors of radio signal attenuation such as antenna height(0.5, 1.0, 1.5, 2.0 m) and the agricultural environment effects (wheat seeding, jointing, and heading) were studied. The relationship between optimal antenna height and radio effective range were found. These tests provide technical supports for wireless sensor network application in agriculture.