Under the condition of super-shallow coverage and small spacing, the tunnel construction is easy to cause large structural deformation. The mechanical properties and supporting effect of tunnel with small spacing are summarized. Finite element software is used to simulate the effect on construction of tunnel group by changing the distance. The results show that with the increase of the distance, the settlement value of the middle tunnel has a smaller and smaller distribution law, when the distance exceeds 3 m, the maximum main stress reduction changes less as the distance increases further, and the research results can provide a reference for the design and construction of similar tunnel group.