The signal quality impacts the precision of the user’s Positioning,Navigation and Timing (PNT) provided by the satellite navigation system.The satellite navigation system must monitor the navigation signal quality and gives alarm.During operating of the system,the signal code correlation peak detection is animportant work inmonitoring,evaluation and control for the navigation signal quality.According to the structure of navigation satellite payload,ICAO (International Civil Aviation Organization) provides the 2OS(2nd-Order Step Threat Model) abnormal signal model,and gives code correlation peak for every abnormal signal.The paper analyses several correlation peak detect techniques based multi-correlator,and gives detection results of the BeiDou system’s navigation signal using the especial navigation signal monitoring system of the BeiDou satellite navigation system.