Abstract: As the theory of calculation method of designing load is immature, and the existing calculation model could not calculate the lining structure of multi-arch tunnel exactly, so there is not a united method to calculate the lining structure. Based on the two slumping arches assumption, a load defining method of multi-arch tunnel is put forward. The interaction between mid-board and lining structure is simulated by pressure springs, and the lining structure calculation model of multi-arch tunnel with compound mid-board is established based on load-structure method. Combing the design and calculation of Fenghuang tunnel in Suzhou, the lining structure is calculated by the model, and the reinforcement ration and stress safety factor are calculated, and this could provide useful discussion on the design and calculation of multi-arch tunnel with compound mid-board.