Near-infrared fluorescent materials include traditional molecular dyes and new quantum dots. Near-infrared spectroscopy belongs to the frequency doubling and main frequency absorption spectroscopy of molecular vibration spectroscopy. It is mainly produced by the non-resonance of molecular vibration when molecular vibration transits from ground state to a higher energy level，and possesses strong tissue penetrability. In recent years，near-infrared fluorescent materials modified by molecular biological techniques have become a research hotspot in medical imaging diagnosis. They have strong tissue penetrability，low background fluorescence interference，high fluorescence signal sensitivity，spectral stability，quenching resistance，molecular targeting recognition and good biological safety. In this paper，the construction of near-infrared fluorescent material and its application in clinical imaging examinations such as ultrasonography，CT，MRI and PET are analyzed. The diagnostic advantages and key techniques of multimodal contrast strategy are discussed，which provide theoretical basis for further clinical application.