Cognitive radio is expected to improve the efficiency of frequency usage, capacity, and dependability of a wireless system. In order to change the radio parameters flexibly, the CR terminal should measure the radio environments on adjacent channels as well as the channel for communication. This paper proposes an overlapped FFT energy detection of adjacent channels with frame summation. The proposed scheme constructs new frame through summation and reduces the energy of the noise at the outputs of FFT. Numerical results obtained through computer simulation have shown that the overlapped FFT with no frame summation and with frame summation improve the probability of detection by about 2% and 3%, respectively, as compared to that without overlapping on the adjacent channel.