Near infrared II (NIR , 1000 Ⅱ ～1700 nm) biological imaging, as a new developing optical imaging technology in recent years, has longer fluorescence wavelength compared with the traditional near infrared I (NIR I, 750～900 nm) and visible light (Vis, 400～750 nm) imaging. Due to the longer emission wavelength, weaker interference by light scattering and tissue autofluorescence, result in higher temporal and spatial resolution with deeper tissue penetration. This technology is more suitable for in vivo imaging in situ. In this review, we mainly introduced research progress on NIR II instrument technology for in vivo imaging, and summarized its major features. Finally, we provided a prospect that the development of chemical materials, optoelectronic instruments, and multi-modal technologies can promote NIR II technology innovation, which is expected to be widely and deeply applied in clinical transformation.