The present disclosure provides an air conditioner and an outdoor unit thereof. The air conditioner outdoor unit includes: a casing; a casing; a main electric control box disposed in the casing; a spot inspection box installed at an outer surface of a side wall of the casing and connected to the main electric control box with a signal wire; and a decorating piece installed detachably at the outer surface of the side wall of the casing and covering the spot inspection box. The air conditioner outdoor unit according to embodiments of the present disclosure has advantages of being easy to be maintained and spot inspected, high water resistance and high security.
