The application provides a frequency spectrum sensing method and device applied to an LTE230 system. A step-by-step detection frequency spectrum sensing method is adopted, and an energy detection algorithm is adopted for coarse detection of 230MHz data transmission radio station signals; when energy values of obtained signals to be measured are not smaller than a first threshold value and not greater than a second threshold value, the energy values are in a low detection precision section for the energy detection algorithm, and a continuous wavelet transformation detection method is used for fine detection of the 230MHz data transmission radio station signals. Compared with a cycle stationary characteristic algorithm of the prior art, the continuous wavelet transformation detection method is advantaged by no need for prior information or known spectrum correlation characteristics of authorized signals, low computation complexity and high detection speed.