The purpose of this paper is to analyze the EM field distribution in U-home which is a smart home of Kun Shan University. It is apparent that wireless devices in U-home become EM field emitters. This paper states the measurement and the analysis of the EM field distribution generated by those devices. The measurements focus on some popular frequency bands, such as 430 MHz, 900 MHz, 1800 MHz and 2.4 GHz. Due to the complexity of EM field interference, a reference field distribution is established by recording the signal strength of the open site outside U-home. All the measured data are compared with the reference data to improve the accuracy of the measurement and analysis. The analysis is useful for locating the wireless devices in U-home to offer not only good communication quality but also low radiation to humans.