Middle frame assembly, cabinet and air conditioner

The invention provides a middle frame assembly, a cabinet and an air conditioner, the middle frame assembly comprises a middle frame shell and a lining plate assembly, the middle frame shell is arranged between a shell assembly and a front panel, and the lining plate assembly is arranged on the side, close to the front panel, of the middle frame shell; the middle frame shell comprises a first appearance strip, a second appearance strip, a first supporting part, a second supporting plate and a third supporting plate, and the outer outlines of the left side and the right side of the middle frame shell are appearance shells; the second supporting plate and the third supporting plate are detachably connected with the upper lining plate assembly or the upper lining plate assembly and the lower lining plate assembly through concave-convex matching structures and/or elastic buckle structures and/or screw fixing structures. According to the middle frame assembly, the structure is reasonable, all the components are co