A microscopy system utilizing a single wavelength excitation to produce both photoacoustic and fluorescence signals was reported. High imaging resolution (<6 μm) can be achieved. With the absorption characteristics of exogenous contrast agents in near infrared, in vivo tumor photoacoustic/fluorescence imaging was realized through this imaging system. The experimental results show that photoacousticfluorescence microscopy has potential application in early tumor imaging and detection. Therefore, by studying and selecting the appropriate dual modal contrast agent, more accurate tissue information and physiological parameters will be provided in different pathological models.