Wi-Fi Direct technology will gradually apply to all kinds of handheld terminals. This paper researches Wi-Fi Direct three-dimensional spatial positioning algorithm on 3D biomedical imaging, combined with a reference node to estimate the distance of unknown nodes, the nodes of the unknown relative positioning. This paper simulates distance correction of both log-distance path loss model and wall attenuation factor model. By RSSI distance measurement model analysis and consequential amendments. The RSSI obtained by at least three known Wi-Fi Direct device from the same unknown Wi-Fi Direct device of a non-visible area are estimated the distance, to achieve three-dimensional spatial positioning of the biomedical imaging device combined with the geometry. Distance measurement model and its amendments are simulated in Wi-Fi Direct architecture based on RSSI and which used to achieve spatial positioning of an unknown device of the non-visible area on biomedical imaging.