An apparatus and method for processing a tender of an aggregate power plant. The apparatus for processing a tender of an aggregate power plant includes an aggregate power plant configuration management unit for generating an aggregate profile by forming an aggregate power plant by grouping distributed energy resources for participating in a power market, a monitoring unit for reconfiguring the aggregate profile by monitoring the distributed energy resources, a tender-processing unit for calculating an offering amount of the aggregate power plant using the aggregate profile, and a tender weight calculation unit for calculating a weight coefficient based on meteorological information in order to adjust the offering amount and for providing the weight coefficient to the tender-processing unit.