Abstract: The detection of navigation signals evil waveform based on multicorrelator is an important issue of GNSS integrity monitoring. This paper defines the effect of 2nd-order step threat model of evil waveform on the code tracking loop, analyzes the multicorrelator technique of detection system based on Local/Wide Area Augmentation System (LAAS/WAAS). From the perspective of simplifying ground integrity channel and shortening the time consumption, this paper puts forward a new technique based on satellite autonomous integrity monitoring. The simulation of the detection capability and efficiency result in a 0.3 Tc decrease of the detection deviation of the technique based on SAIM with a 20 dB increasing of SNR over the technique based on LAAS, which makes a great significance of integrity monitoring.