The invention relates to a digital signal adaptive code rate estimation method and device based on multi-wavelet basis combination. The method comprises two steps of preprocessing and adaptive code rate estimation. In the preprocessing step, original I/Q data of an observation window is used as input, and a bandwidth rough estimation result and baseband I/Q data in a specified oversampling range are output through fast Fourier transform, frequency estimation, bandwidth rough estimation, down-conversion and down-sampling processing; in the adaptive code rate estimation step, the wavelet transform scale is adaptively selected according to a bandwidth rough estimation result, wavelet transform is carried out on the baseband I/Q data, jump information after transform is extracted, and finally,the code rate of a digital signal and a wavelet basis for signal acquisition are output through adaptive decision. According to the method, the problems of single wavelet basis application range andlow estimation precision of the traditional wavelet transform-based digital signal code rate estimation are solved, the accuracy of the digital communication system code rate estimation under the non-cooperative condition is improved, and the method can be applied to the fields of spectrum monitoring, electromagnetic reconnaissance and the like.