It is very urgent to design higher speed FFT processor due to higher requirement in LTE-Advanced system. In this paper, we propose a new parallel cascade architecture for FFT processor. The architecture, which combines advantages of parallel with that of cascade architecture, is flexible in parallel grade. To simplify accessing memories, propose a new address mapping scheme, too. With the property of in-place operation, only a RAM is used to store in-out data. The scheme is very efficient for generating SC-FDMA baseband signal in LTE-Advanced system.