Orthogonal frequency division multiplexing (OFDM) transmission has become a popular technique for modern wired and wireless communications. Next-generation mobile communication systems also plan to adopt orthogonal frequency division multiple access (OFDMA) technology for multi-user scenario, in which subcarriers can be grouped as resource blocks or subchannels and allocated to different users. Hence, only partial subcarriers in one OFDM symbol may be used by one user end (UE). In this situation, more (a) Partial FFT algorithm (b) Cached-FFT algorithm redundant power consumption is produced by the complete FFT computation for OFDM demodulation in the UE. Among the available FFT architectures, cached-FFT has much regularity and lower power consumption than others. Thus, a partial FFT algorithm can be applied to the cached-FFT architecture for power reduction of OFDMA UE. In this paper, a partial cached-FFT algorithm is proposed to control the operation of the cached-FFT processor for different proposals of OFDMA resource block allocation schemes, thereby reducing the computing power.