Aiming at the technical problems of simple anti-interception method and insufficient anti-interception ability in traditional spread spectrum， frequency hopping and time hopping techniques，， an anti-intercept technology based on weighted-type fractional Fourier transform（WFrFT） and modulation hopping is proposed. The properties of the original signal have been changed with the constellation rotation， expansion and diffusion by WFrFT. Meanwhile， combined with modulation hopping technology， different carrier frequencies correspond to different signal modulation modes. The proposed method improves the confidentiality and security of information transmission in the complex and changeable electromagnetic environment.