From the view of trick recognition, features of signal decomposition structure in existing frequency estimation methods were analyzed, based on which, a frequencyshiftdomain decomposition structure was proposed. A compound signal was constructed by combining several simple signals corresponding to different times. The given information in the time domain can be adopted to form an information accumulation effect, such that the interference frequency and noise can be suppressed effectively by decreasing the calculation. To match the use of a frequencyshiftdomain decomposition structure, a frequencyshift equilong iterative algorithm suitable for equilong signals was proposed. Simulated experiments were carried out in numerous application environments. The results show better noise immunity and realtime performance as well as higher frequency estimation precision.