The invention provides a control method of an outdoor side fan of an air conditioner. A first relationship table among a reference rotating speed of the outdoor side fan, a reference temperature of anoutdoor environment and a reference frequency of a compressor of the air conditioner is preset in the air conditioner. The control method of the outdoor side fan of the air conditioner comprises thefollowing steps: acquiring the actual temperature of the outdoor environment and the actual frequency of the compressor; acquiring a target rotating speed of the outdoor side fan through a bilinear interpolation method according to the actual temperature, the actual frequency and the first relationship table; and controlling the outdoor side fan to work at a target rotating speed. The rotating speed of the outdoor side fan can be controlled more finely, and the rotating speed of the outdoor side fan will not fluctuate greatly as a result of fluctuation of the outdoor environment temperature and the frequency of the compressor in at least part of or full time period of the air conditioner in operation, so that the system stability is improved, the noise of the outdoor unit is improved, theservice life of the outdoor side fan is prolonged, and meanwhile, the excessive rotating speed of the outdoor side fan is avoided, so that the outdoor side fan is more energy-saving and power-saving and the energy efficiency of the air conditioner is improved.