The classification of egg is very important in egg production. Put forward an automatic classification device based on machine vision technology on the basis of research at present situation of egg classification home and abroad. Positioning of the egg body is the key to determine the accuracy of classification. At present, the egg body positioning usually use position sensor as it is connected by cable, it's not convenient to install and use. The study of wireless position sensor based on ZigBee ,design the receiving device of wireless position sensor. Proved by the experiment ,errors of the proposed device was 0. 1% , the maximum transfer distance was 100 m, the transfer distance of sensor node was 50 m, and the loss rate of network passage was 0. 89%. The power consumption was decreased with different collecting frequencies and sleep mode. The proposed device could meet the measuring requirement.