The present invention relates to an apparatus and method for recycling coal ash comprising an unburned coal ash recovery unit and a lightweight aggregate manufacturing unit and is provided in an existing thermoelectric power plant and in which coal ash generated in the thermoelectric power plant is completely recycled for specific purposes using the coal ash recycling apparatus. According to the invention, the surrounding environment can be prevented from being contaminated during the transportation of waste to a recycling factory and transportation expenses can be reduced. Moreover, coal ash is completely recycled for specific uses, such that unburned carbon contained in the coal ash can be used. Also, coal ash can be recycled even as concrete admixtures having strict standards. In addition, the present invention can prevent environmental contamination caused by the landfilling of waste and recycle waste, thereby reducing the loss of land and the waste of resources.