Abstract: Study on crossing shock waves/transitional boundary layer interaction in the double vertical wedges configuration was carried out using wind tunnel tests and numerical calculations. The wind tunnel tests were carried out at Φ600 mm pulse combustion wind tunnel. The Mach number of the free stream condition is 3.0, and the unit Reynolds number is 2.1 × 10⁶ m⁻¹. The schlieren images, wall pressure and wall heat fluxes were obtained during the tests. The results show that because of the adverse pressure gradient caused by the crossing shock waves, the separation of the laminar boundary layer was captured near the shock waves intersection point. And the transition from laminar to turbulent occurred rapidly in the interaction region. After installation of vertex generator devices or roughness devices, the boundary layer transition position moved to the upstream of the interaction region, the separation was effectively inhibited. And the heat fluxes in the interaction region declined obviously. The peak value of heat fluxes was reduced by more than 25%. The shock wave structures and wall pressure distributions obtained from tests and simulations agreed well, while the prediction heat fluxes were much larger than the test results. The comparison between the calculated results of the transition model and the turbulence model shows that the obviously larger turbulence viscosity is the main reason why RANS methods over-predict the heat fluxes in the unseparated interaction region.