An efficient palladium-catalyzed protocol for the synthesis of 4-bromoisoxazoles derivatives in moderate to good yields from readily available O-methyl oximes in basic ionic liquid has been developed. Their structures were confirmed by 1 H NMR, 13 C NMR and HRMS. This cascade cyclization/bromination process provides a novel route for directly accessing 4-bromoisoxazole in good to excellent yields and good functional group tolerance with high atom efficiency. Notably, the current methodology could also be conveniently applied to the synthesis of isoxazoles naturally occurring biologically active frameworks.