Disclosed are a large-scale composite synthesis system, a reactor therefor, and a synthesis method using the same, wherein two or more different samples are vaporized in respective vaporizers, and are then fed into a reactor that has a relatively large transverse cross-sectional diameter compared to the connector for transporting the samples in a gas phase and is maintained at a temperature lower than that of the connector, thus producing a powder composite, the composite being synthesized while being electrostatically attached to an adherend surface.