Research conclusions: ( 1) In bridge － tunnel connection section in series，using enlarged cross － section and digging filling piles can effectively solve the problems that bridge abutment enters tunnel difficultly and aerodynamic effect exists in tunnel portal． ( 2) According to different portal types and lengths of open cut sections，excavation methods of bridge abutment pits are classified into two types: protection of digging filling piles and step － slope excavation behind the pit in bridge － tunnel docking connection section． ( 3) For the situation that retaining wall exists outside of the portal in bridge － tunnel docking connection section，the following two measures that pile foundation and joist are set under the retaining wall and the retaining wall is designed into anchor retaining wall，can solve the difficult problems that the retaining wall is unstable because of pit excavation． ( 4) By the measure that transition section is set in tunnel portal，cable channels can link smoothly in bridge － tunnel connection section． ( 5) Inspection well which is set in the lower tunnel portal，can effectively solve the drainage problem of tunnel．