Flat-field achromatic microscope objective

The utility model provides a flat-field achromatic microscope objective which sequentially comprises a first lens with positive focal power, a second lens with positive focal power, a third lens with positive focal power, a fourth lens with negative focal power, a fifth lens with positive focal power, a sixth lens with positive focal power and a seventh lens with positive focal power from an object side to an image side along an optical axis. An eighth lens with positive focal power, a ninth lens with negative focal power, a tenth lens with negative focal power, an eleventh lens with positive focal power, and a twelfth lens with negative focal power; wherein a diaphragm is arranged between the third lens and the fourth lens, the microscope objective is reasonable in structural design, has high magnification, solves the problem of chromatic aberration, and is high in measurement precision. In addition, the working distance of the microscope objective can reach 3.5 mm, and the problems that an existing objectiv