The invention provides a recycling system for fly ash. The recycling system comprises a separation device, a balling device and a microwave heating device. The separation device is connected with a fly ash storage bin and is used for separating the fly ash to obtain coarse ash and fine ash, wherein the grain size of the coarse ash is smaller than 1000 mesh, and the grain size of the fine ash is larger than 1000 mesh. The balling device communicates with a coarse ash outlet of the separation device and manufactures wet balls through the coarse ash, a bonding agent and water. The microwave heating device communicates with an outlet of the balling device and is used for sintering the wet balls into ceramsite. By means of the recycling system, the fly ash of power plants is utilized in a classified manner, the fly ash discharged by the power plants at present is completely utilized, the zero-emission effect is achieved, and the pollution problem caused by the large-amount emission of the fly ash of the power plants to the environment is solved.