Abstract: Using approximate function of film density distribution in radiation field,the uniformized film density distribution is derived.A radiation film density compensation and uniformizing method based on compensation factor and uniformizing ratio is proposed.Then,the relation among diameters of compensation block,inspection parameters,and material attenuation is discussed.Uniformizing limit condition is obtained.Two compensation blocks made of aluminium alloy are designed with uniformizing ratio=0.82,0.88,and are used in the experiments.Uniformized density distributions and uniformizing ratio measured in the experiments almost conform to the theoretical design.The research results show that applying this method to compensate density of radiation field can realise density uniformity in radiographic testing.