The dynamic model of a kind of Turbofan EEC ( Engine Electronic Controller ) main fuel passage belongs to nonlinear time - varying system, it is difficult to identify the model because of the singularity caused by disturbance of the diverse - structure response. Based on the theory of exception - checking and error - filtering of wavelet transform, the response data is analyzed and reformed, the singularity is obtained, and the characteristic of the dynamic model is identified by segment. The result shows that wavelet is applicable to the singularity identification, exception - checking and error - filtering without experienced knowledge of the procedure error.