As impurities always plague real experiments,we report here a study on the effect of impurity on the dynamic scaling behavior of hysteresis.The model used is the two -dimensional Ising model with quenched random non-magnetic impurities.The results show that for any temperature below the critical point,there exists a corresponding critical concentration of impurities that serves as the critical point in the pure model for distinguishing the scaling behavior of hysteresis.The hysteresis loop area A,representing the dissipation per cycle,scales with the scanning rate of the external field R as A=A0+aRn, with a nearly constant n～1/3, weakly dependent on the concentration,and a finite area A0 even for vanishing small rates below the critical concentration.While above it, A0=0 and n increases significantly with the concentration. This behavior is similar to the pure system.Thus in the concentration -temperature phase diagram there is a regime within which the scaling relation and its exponent of the pure system are robust with impurities.