Electromagnetic compatibility analysis and electromagnetic effect evaluation of an aircraft illuminated by an external electromagnetic field are of great significance to flight safety. For this purpose, electromagnetic coupling analysis is needed to evaluate the Shielding Effectiveness(SE) of the aircraft cabin. Due to the high computational cost of full-wave analysis methods and the phenomenon of high frequency response sensitivity, the Power Balance(PWB) method based on statistical electromagnetics is more suitable for SE analysis for the aircraft cabin. An analysis program based on PWB method is developed, whose correctness and effectiveness are verified by comparing with literature results. The program is utilized to analyze SE of an aircraft cabin under various conditions. The obtained results contribute to understand how the various factors such as wall conductivity, portholes, passenger loads as well as internal receiving antennas affect the SE.