The invention discloses an internal rectal optical, optoacoustic and ultrasonic multimode imaging endoscope which comprises a sleeve, an optoacoustic signal activating component, an ultrasonic signal activating and collecting component, an optical imaging component and an image reconstructing and displaying component. A device comprises a compact internal rectal optical, optoacoustic and ultrasonic multimode imaging endoscope, three kinds of imaging can be performed simultaneously, multi-parameter physical information and multi-scale structural images in recta can be acquired. The invention further provides a configuration scheme of the whole device and a method for utilizing the device for imaging. Three imaging techniques are highly integrated into one set of instrument, each imaging technique is optimized, and combination of three rectal endoscopic imaging methods of optical imaging, optoacoustic imaging and ultrasonic imaging is realized. The integrated endoscope combines specific advantages of three imaging modes, rectal physical images with multi-parameter information and multi-scale structural characteristics can be acquired, and application requirements of a rectal endoscope on medicine can be met better.