Information entropy theory was introduced into this paper for aero-engine health monitoring in combination with symbolized multiple parameters time series.The joint entropy of symbolic series

which depicts the disorder degree of aero-engine performance parameters

was used to analyze aero-engine health condition and evolutive trend.Experiments of two data sets were done

and the results show that the method described in the healthy evolution of aero-engine coincides with the actual situation.The method can reflect the health condition and also can be applied in aero-engine health monitoring.