According to the integral panel design method in “aircraft design manual”, the structure with the higher bearing capacity can be obtained in the optimum design of area ratio. However, the determination of the separation position between skin and stringer causes great obstacles to the acrual design. For T-shaped integral panels with skin thickness ranging from 4—6 cm, the optimum design area ratio of skin to stringer is obtained under given sparation position and the maximum unstable load under certain structural quality. Thick skin T-shaped monolithic panels designed with this area ratio have the strongest ability to withstand axial load.