The invention provides a running control method, a running control device and an air-conditioner. The running control method is suitable for outdoor draught fan assemblies of the air-conditioner; the running control method includes the steps that working condition environment records and running parameter records of the outdoor draught fan assemblies under the power-on state are determined; corresponding dust extraction periods are determined according to the working condition environment records and the running parameter records; within one dust extraction period, the outdoor draught fan assemblies are controlled to reversely rotate and run. According to the technical scheme, on one hand, the possibility of not-clean dust extraction caused by the too short dust extraction period is reduced; on the other hand, the possibility of too high power dissipation caused by too long dust extraction period is reduced, under the normal using condition of the air-conditioner, efficient dust extraction on the outdoor draught fan assemblies can be automatically carried out, the running efficiency of an outdoor heat exchanger is optimized, and the economic cost and the time cost of manual dust extraction are reduced.