Aiming at the problems of large base time series step quantity base, many step parameters and low efficiency of manual interpretation in the ejector electrical system, a two-step interpretation method of time series difference matrix discrimination and step amplitude mapping is proposed. Initially, the time series difference matrix discrimination method is used to identify and mark the time series steps. Then, through the step amplitude mapping method, the correctness of the large cardinal steps identified by the time series difference matrix is automatically interpreted according to the instruction library, and the interpretation results are converted to the corresponding mapping domain according to the mapping rules to eliminate the influence of a large base of timing steps on interpretation. Finally, the method is experimentally verified. The results show that the proposed interpretation method can efficiently and accurately realize the automatic interpretation of large-base time series steps, and the interpretation efficiency is greatly improved compared with the traditional manual interpretation.