To enhance the reliability of transient gas path analysis for aero engines under multi-component degradation, taking the reverse-flow-core intercooled turbofan engine (RITE) as the research object and proposes a novel gas path analysis method based on dynamic effect compensation. This method not only takes into account the rotor dynamics effect in the transition state process, but also simultaneously considers the influence of the heat soakage effect, volumetric effect brought about by the operation of the compressor, combustion chamber, turbine and intercooler components, as well as the lag response effect existing when the sensor feeds back the measurement parameters. The continuous prediction of the health status of each component of the engine is achieved by using the Newton-Raphson iterative algorith and time series measurement data. The simulation test results of the diagnostic accuracy and speed of the proposed method show that when the faults of each component of RITE are constant during the transient process, the maximum diagnostic error, average error and average calculation time of the single-step size of this method are less than 0.0037%, 0.0007% and 0.061s, respectively. When abrupt faults occur, the maximum and average relative errors are less than 0.0055% and 0.0006% respectively, and the average diagnosis time is less than 0.065 seconds, verifying the accuracy and robustness of the proposed method.