Abstract: Based on the structural theory of Petri nets, the boundedness and liveness monotonicity of a subcategory of asymmetric choice (AC) nets, new extended strong asymmetric choice (NESAC) nets, were studied. The sufficient and necessary condition for determining structural liveness and boundedness of an NESAC net is that N is covered by a cluster of siphons and every nonemptyminimumsiphon must be a trap and satisfiest ∩H=t ∩H=1.NESAC net has the same characteristic of liveness monotonicity as ESAC net does.