The controlled-source electromagnetic method (CSEM) has been widely used for geophysical surveys, such as controlled-source audio-frequency magnetotellurics (CSAMT) for mineral explorations. Many types of signals are hired for different CSEM applications, such as square wave,2n sequence pseudo-random waveform, binary symmetric wave, and other specific waveforms for MCSEM. In frequency domain CSEM exploration, it is often to change the frequency of transmitting signals to obtain more information from the subsurface, which is sometimes time-consuming. Under such circumstances, we propose a novel method for adaptively constructing a wide-band, high-frequency-density pseudo-random signal. Based on this method, we successfully combine all interested frequencies into one waveform, with the energy of the interested frequencies uniformly or almost uniformly distributed. Benefit on that, for most frequency domain CSEM cases, exploration can be conducted by only one signal. This new kind of signal can significantly improve exploration efficiency compared with the past transmitter waveforms.