Based on the unsteady characteristics of the flow field under crosswind， a numerical model including crosswind， tunnel， and train was established and the influence of tunnel type on aerodynamic pressure， flow field characteristics， and the aerodynamic load of HST in the process of leaving a tunnel under crosswind was studied. The results show that the aerodynamic pressures at the tunnel exit are the most significantly affected by the tunnel type. The change magnitude of aerodynamic pressure on the windward and leeward side of the train in a single-track tunnel （STT） are 15.7% and 22.6% greater than that in a double-track tunnel （DTT）， respectively. The blocking ratio is the primary cause of the apparent difference in aerodynamic pressure in STT and DTT under the same train type， train speed， and crosswind conditions. The distances between the separation vortex formation position and the nose tip of the head vehicle （HV） are the same， but the leeward side of the train driving out of DDT has a greater degree of flow field offset； The flow field distribution around the head vehicle and the middle vehicle （MV） are basically the same and less influenced by the tunnel type， while the tunnel type more influences the flow field distribution characteristics of the tail vehicle （TV）. The aerodynamic load of the TV is more sensitive to the tunnel type. The side force cofficient and lift cofficient amplitude of TV in DTT are 27.3% and 7.1% larger than that in STT， respectively. When an HST leaves tunnels with a crosswind， it is suggested that the effect of the tunnel type on the aerodynamic performance cannot be ignored.