At present, the noise of domestic air conditioning units in actual use is too high, and the fan vibrates, which is easy to burn out the motor. In view of these common problems, the causes and influencing factors are analyzed by research, and specific improvement measures and methods are proposed from several aspects such as the calculation of air conditioning system, the selection of fan and the structure of air conditioning unit. It is also pointed out that in order to optimize the performance of air conditioning units, designers and equipment manufacturers need full cooperation to continuously improve the structure of air conditioning units and make them more reasonable and perfect.