The invention discloses a three-dimensional 
endoscope system compatible with two-dimensional endoscopes. The three-dimensional 
endoscope system comprises a first object lens, a second object lens, a first image transmission column, a second image transmission column, a first image diaphragm, a second image diaphragm, a first focusing lens group, a second focusing lens group, a first deflection 
prism, a second deflection 
prism, a first 
cylindrical lens and a second 
cylindrical lens. The three-dimensional 
endoscope system has the advantages that the first deflection 
prism is used for reflectingfirst light beams which are received by the first focusing lens group and are projected from the first focusing lens group, the second deflection prism is used for reflecting second light beams whichare received by the first focusing lens group and are projected from the second focusing lens group, accordingly, the distances between the optical axes of the 
first light beams and the second light beams can be changed, and the three-dimensional endoscope system can be matched with image sensors of two-dimensional endoscope systems; the first 
cylindrical lens is used for compressing the 
first light beams reflected from the first deflection prism, the second cylindrical lens is used for compressing the second light beams reflected from the second deflection prism, and accordingly flattened first images and flattened second images can be acquired by 
first light sensing regions and second 
light sensing regions of the image sensors.