Green fluorescent protein (GFP) transfected Hela cell was planted in naked mice, to construct an in vivo model for monitoring the therapeutic effect of laser hyperthermia in real time. A cooled CCD fluorescence imaging system was used to record the tumor fluorescence image during the hyperthermia process. Primary experimental results were presented in this paper. To make sure the fluorescent probe GFP does not have strong effect on the biologic function of the host tumor cell (Hela cell), several conventional biological processes were observed in real time. First, neurons, which are much more tender than tumor cells, were transfected with GFP (cameleons). No morphological inhomogenities were observed, and normal functional responses of the neurons were observed when stimulated with histamine. In the second step, the mitosis process of cultured Hela cell was monitored. The features observed during mitosis confirmed that the transfection does not ruin the mitosis process of the tumor cell. At last, naked mice with tumor cell was constructed, which emit fluorescence in the tumor region when excited with faint laser. This presentation provides an in vivo biological model for quick monitoring of the therapeutic results of tumor hyperthermia.