A secure communication method based on multi-parameter fractional Fourier transform and constellation scrambling relates to the field of secure communication. The purpose of the invention is to enhance the information security performance of conventional method in the process of communication. A signal transmission method of the secure communication method is as follows: digital baseband mapping is carried out on data source signals, series/parallel conversion, N-point multi-parameter weighted fractional Fourier transform, constellation scrambling and cyclic prefix addition are sequentially carried out, and after parallel/series conversion, digital/analog conversion and up-conversion processing, a N-point scrambled sequence is transmitted into a channel. A signal receiving method of the secure communication method is as follows: after down-conversion, analog/digital conversion, series/parallel conversion, cyclic prefix removal, constellation descrambling, N-point multi-parameter weighted fractional Fourier transform, parallel/series conversion and digital baseband mapping are carried out on the received signal, the original data source signal is obtained. The secure communication method is applicable to the process of secure communication.