Three-dimensional shock interactions are commonly encountered on the V-shaped cowl lips of inward-turning inlets in the wide-speed range flight. The evolution of shock reflections on a V-shaped blunt leading edge （the crotch radius over the leading-edge radius R/r=1， the half-span angle β=18°） with the variation of freestream Mach number （Ma_∞） is investigated using numerical simulations methods and wind tunnel experiments. The results indicate that the interactions between the detached shocks on the two swept branches can generate both regular reflection （RR） and Mach reflection （MR）. A hysteresis appears in the transition between RR and MR depending on the increase or decrease in Ma_∞. When the initial reflection type is RR， large-scale flow separations and separation shocks occurs at the crotch. With Ma_∞ increasing from 5.7 to 6.5， the intersection point between the detached shocks moves downstream and coincides with the intersection point between the separation shocks， which causes the transition from RR to MR. When the initial reflection type is MR， a large-scale counter-rotating vortex pair occurs at the downstream of Mach stem. With Ma_∞ decreasing from 6.7 to 5.9， the counter-rotating vortex pair no longer affect the detached shocks， which causes the transition from MR to RR. A wind tunnel experiment confirmed that the dual-solution of RR and MR exist at Ma_∞=6. The flow structures， including the intersection point between the detached shocks， the intersection point between the separated shock， and the size of the counter-rotating vortex pair are identified to establish a transition criterion of RR?MR. In the dual-solution domain， the maximum wall pressure in RR is approximately 2—3 times of that in MR， indicating that the hysteresis causes a sudden change in aerodynamic loads on the cowl lips.