Disclosed in the present invention is a body fluid imaging system, a body fluid imaging method and a depth of field extension imaging device. The depth of field extension imaging device includes: an interface unit for receiving the light refracted and/or reflected by the body fluid sample in a current body fluid sample container; and a depth of field extension unit for carrying out wavefront coding and convergence processing on the light received by said interface unit. By means of the system, method and device of the present invention, the time needed by the imaging process can be reduced, thus improving the productivity of the system; and error generated due to frequently adjusting the relative position between the body fluid sample container, the depth of field extension imaging device and the image sensor can be avoided, thus improving the reliability of the system.