To solve the crossing-linkable polyethylene(XLPE) insulation compound purity evaluation problem,a high speed scanning measurement system is designed according to Linear CCD technology.The inspecting system of defects in cable materials based on CCD obtains signals of defects in cable materials with irradiation of parallel light,by using linear array CCD control circuit.The defect signals are collected and transferred by using virtual oscillograph DSO-2902,and the defect signals are analyzed and processed by using computer.The defects are precisely figure out.The data of signals memorized in computer are processed by using software system of data collecting,the data quantity to be processed is decreased greatly,while the contamination information data are reserved.Thereby,the inspection of precise size and location of defects are achieved.The experiment results show that the proposed system can measure both the transverse and the longitudinal size of the XLPE contamination particle well and truly,and also detect the accurate positions and the number of a certain kind of impurity particle.The acuity of this system can reach 20 μm and the error ratio is less than 5%.The detecting ratio of the contamination particles can be high up to 100%.