With complex configuration, the general whole-body fluorescence optical imaging system is power-consuming for it is mainly composed of laser or mercury lamp, filter and fiber-optic cable. In this paper we aimed at setting up a compact imaging system based on power light emitting diode (LED). We first discussed fluorescence excitation efficiency of mercury lamp and LED. Then we developed a compact prototype whole-body fluorescence optical imaging system based on power LED. With the prototype, we monitored the dynamic course of green fluorescence protein (GFP) expressing tumors in the same intact nude mice. We also recorded the temporal behavior of the infectious process of GFP-expressing bacteria from outside intact infected animals. This study puts forward a platform for monitoring tumor growth. The experiment reveals that it is doable to substitute power LED for mercury lamp for whole-body fluorescence optical imaging.