The dust produced during construction of large crosssection tunnel cannot be easily exhausted by construction ventilation. Hence, field monitoring is carried out on dust concentration under conditions of drilling, blasting, mucking, spraying, etc.; the dust distribution characteristics under different constructions are numerically simulated according to monitoring data; and the dust control measures for large crosssection tunnel construction are put forward. It is showed that the dust concentrations under mucking and spraying exceed limit much. It is concluded by numerical simulation that: (1) The dust concentration in the area 40 m close to the excavation face is unstable, the downward trend is not obvious. (2) In order to ensure that the fresh air arrives at the excavation face with a larger spray surface, the distance between duct pipe end to excavation face is recommended to be 60 to 80 m when arranging the ventilation pipes. (3) It is recommended to use the wallhung wind pipe dust reduction + vehiclecarried dust removal scheme, whose dust removal efficiency can reach 95%, and which can effectively reduce the dust concentration in various areas of the tunnel, and has little impact on construction.