The invention discloses an endoscope and an optical information processing method. A light source is used for producing first-wavelength light and second-wavelength light. The first-wavelength light and the second-wavelength light sequentially pass through a first polarizer, a first beam splitter mirror and a self-focusing lens to reach a beam splitter plain film. The first-wavelength light is reflected by the beam splitter plain film, passes through the self-focusing lens and then is reflected to a second beam splitter mirror by the first beam splitter mirror, and then the first-wavelength light sequentially transmits the second beam splitter mirror and a second polarization detection device to reach a first optical sensor. The second-wavelength light penetrates through the beam splitter plain film to reach a detected tissue sample, the detected tissue sample is scattered, second-wavelength polarized light carrying polarization information of the detected tissue sample transmits the beam splitter plain film and the self-focusing lens to reach the first beam splitter mirror, and the second-wavelength polarized light is reflected by the first beam splitter mirror to reach the second beam splitter mirror and is reflected by the second beam splitter mirror to reach a second optical sensor through the second polarization detection device. The endoscope can be miniaturized, and imaging quality is improved.