The invention provides an air conditioning unit. The air conditioning unit comprises an outdoor main case. A compressor and a condenser are collected inside the outdoor main case. A fixed device which is connected with the connecting portion of an exhaust pipe and an inlet pipe of the condenser is arranged inside the outdoor main case. The fixed device comprises a base arranged on the outdoor main case, a connecting ring which surrounds the exhaust pipe and is tightly attached to the exhaust pipe and a bolt, wherein one end of the blot is fastened with the base, and the other end of the bolt is connected with the connecting ring. By additionally arranging the fixed device, the partial vibration of the exhaust pipe can be transmitted to the outdoor main case or collected by other components inside the main case. The vibration generated when the compressor is started or shut down, and an air condition is in use can be blocked or receded in maximum. The tubing fracture and welding spot cracking which are caused by the pipeline fatigue due to the fact that tubing connected with the exhaust pipe vibrates in long-time can be avoided.