Aimed at the problem that within a certain time, the non target receiver can still get the parameter of the demodulation parameters effectively through parameter scanning in the 4-WFRFT covert communication system, this paper proposes a satellite covert communication system by using the double layers multiple parameter weighted-type fractional Fourier transform (DL-MPWFRFT) and constellation scrambling is proposed. The paper proposes DL-MPWFRFT based on multi parameter WFRFT. The hiding principle and characteristics are analyzed through the research of constellation. Though increasing the signal concealment, the constellation scrambling phase increases again after DL-MPWFRFT signal conversion. Finally, from two aspects, the comparison of error rate and the number of parameter scans, the anti interception advantages of the proposed system are described qualitatively and quantitatively. By comparing the BER of the system, the result shows that even if the SNR is 15 dB, the BER of the non target receiver is still more than 0.4. The non purpose receiver obtains the correct demodulation parameters by parameter scanning, which needs (M/0.000 5)2 scans.