Abstract: According to the limit support pressure at excavation face of shield tunnels, the principles for calculating the covered earth pressure of tunnels in different strata are proposed by comparing the theoretical calculation with the field measurement, and the limit state equation for excavation face stability is deduced by using the slice method to analyze the excavation face stability of shield tunnels. Hereby, the limit support pressure at excavation face of shield tunnel can be solved. Finally, based on the specific engineering practice, the aforementioned theories and methods are used in searching the critical sliding surface and calculating the limit support pressure. The research results are important in guiding the design and construction of shield tunnels.