Abstract: Based on the three-dimensional finite element numerical simulation, an evaluation method of pig cleaning capacity was innovatively proposed from the perspective of the contact friction characteristics of the sealing component. Three-dimensional finite element models were established for two kinds of typical pigs running in horizontal straight pipeline with ANSYS, and the accuracy of the models was verified by field tests. Further, the cleaning capacity of the two kinds of pigs under different friction conditions were compared respectively through analysis on the calculation results. The research results show that the contact friction coefficient can affect the sealing tightness, tangent scraping force and effective cleaning area of running pigs. The scraping force increases with the increasing of friction coefficient while the sealing tightness and the contact area decrease. If the material and interference of the sealing components are identical under the same friction condition, the sealing tightness and the scraping force of the straight plate pig are superior to those of cup pig. However, the effective cleaning area of the cup pig is larger than that of the straight plate pig with same running distance. Appropriate pig should be selected according to the type of impurity in the pipeline to be cleaned, so that the cleaning capacity and efficiency can be improved effectively.