Abstract: The finite element numerical analysis method is adopted to solve the boundary value problem of additional stress distribution in subsoil of civil airport runway under aircraft load, and the effects of the aircraft load types, slab thickness of rigid pavement and subsoil resilient modulus on service depth are quantitatively analyzed. Heavier aircraft load and more complicated landing gear configuration lead to greater distributional zone and corresponding service depth. The service depth decreases with the increasing slab thickness of rigid pavement, but increases with the increasing subsoil resilient modulus. The relations between the service depth and the slab thickness of rigid pavement and the subsoil resilient modulus are both linear and depend upon the definition standard of the service depth. Based on the analysis, a simple method for determining the service depth of rigid pavement is proposed to avoid the complicated numerical analysis. The findings can be referenced for determining the service depth of airport runway, subsoil treatment depth and treatment method in the design and construction practice.