An object of the present invention is to provide a biological feature composite imaging technology that multiplexing of the imaging functions and a mobile terminal comprising said composite imaging system. The composite imaging system comprises: a lens assembly (130); an optical filter assembly (120) including at least a visible light bandpass region and an infrared light bandpass region; an image sensor (110) that includes a visible light imaging region, an infrared light imaging region, and a transition region between said two regions, said image sensor (110) operating under one of the visible light imaging mode and the infrared light imaging mode. Under the infrared light imaging mode, specific physical properties of the biological features are used as the image quality information to realize auto-focus of the biological features in the region of interest.