Abstract: Along with the improvement of the aircraft control surface of the modified type x-x, a general program for isoparametric element analysis is carried out for the surfaces,which are constructed with sandwich structures of Nomex honeycomb core and carbon fiber plank, solid carbon fiber beam, and front cored part. The principle and theoretical basis of the computation are analyzed, and a computational model as will as its programing is also recommended.The program is implemented on the IBM-PC microcomputer or thier compatible computers, thus the expenses of computation can be saved greatly. It can also be applied to wings, floors, hatches etc. Cdmparision of the calculated with existing experimental results for x trimmer shows that the calculated strain, stress and displacement distributions are reasonable and are satisfactory for aviation engineering applications.