Provided are a system for channel sounding of broadband single carrier mobile communications and a method thereof. A channel sounding device is provided, which achieves precise modeling of a broadband mobile communication in a 5 GHz band. The channel sounding device can perform precise channel modeling by collecting broadband channel data of 20 MHz between a base station and a mobile station moving at maximum 150 km/h, using a sounding signal including a 802.15.3 preamble, a maximum length sequence (MLS) signal, and a single carrier frequency domain equalization (SC-FDE) symbol overcoming a limitation of signal distortion of an orthogonal frequency division multiplexing (OFDM) signal. The channel sounding device can simultaneously perform modeling of interference of an adjacent channel as well as a transmission channel.