The characteristic structure of compound electrocyclone(CEC)and the fundamental princi- ple of catching dust were studied.According to the force suffering analysis and dynamics similitude of containing dust airflow in CEC,the simularity criterion of electrocyclone in cold modeling were educed and the electrostatic-centrifugal separation simularity criterion was provided.The approximate model- ing conditions of CEC were made definite.A great number of experiments obout the affecting factors on dust collection performance were completed with the established cold modeling system.The calcula- tion formulas for total dust collection efficiency and total resistance coefficient were set up by means of disposing experimental data with multiple linear regression algorithm.The results are helpful to design CEC.