The preparation of pure and Ni-doped ZnO from different ingredient by coprecipitation method. Then the Comparison on the response of pure and Ni-doped ZnO sensors on different Ni concentration to 20ppm acetone was investigate for the sake of finding Ni dosage of the sensors under optimum response.OnSthisSbasis, Au was added into this sensors for activate these.TheSexperimentalSresultSindicatedSthat 1mol% Ni-doped ZnO sensors are better than other sensor without Au activation.Further 0.03mol% Au activated 1mol% Ni-doped ZnO has the showStheShighest acetone gas response in all sensors and it also maintain high selective over ethanol,formaldehyde,acetone and rapid response-recovery time under this condition.