A kind of fluorescence endomicroscopy which can be used for in-vivo imaging in diagnosis and photodynamic therapy is described. According to the fluorescence signal intensity detected, the fluorescence endomicroscope can adjust the excitation power in different regions rapidly using feedback algorithm, to obtain high signal noise ratio (SNR) and high dynamic range images, and achieve interactive fluorescence diagnosis and photodynamic analysis. It can also adjust the light dose continuously according to the feedback treatment effect, getting the best results of photodynamic therapy. Dynamic adjustment of excitation intensity is realized by the ON-OFF state and the residence time of computer-controlled digital micromirror device. The outer diameter of the fluorescence endomicroscope is 8 mm, working length is 250.3 mm. It can be assembled in the sheath tube of standard laparoscope, and adapted to in vivo microscopic imaging diagnosis of the lesion easily. The experimental results show that the field of view is 600 μm, optical resolution is better than 2.2 μm, and the image dynamic range can be enhanced more than 200 times. The fluorescence endomicroscope can improve the details and SNR of fluorescence saturation regions and fluorescence weak regions, and improve diagnostic accuracy at the same time. This technology can be extended to confocal 3D imaging further, and achieve in vivo histological analysis.