Switching-mode power supply (SMPS) connects the power supply and load through the long cables. Radiated electromagnetic interference (EMI) becomes more serious because of the significant increase of switching frequency. It is necessary to analyze the generation mechanism of radiation EMI. Aiming at the problem that the wiring features of the cables are not taken into account in the radiation EMI model of the SMPS device and the accuracy of radiation EMI prediction needs to be improved, a radiation EMI emission model considering bending positions and angles of cables has been proposed, which can accurately predict the radiation EMI of SMPS. Finally, an experimental platform is built and the correctness of the proposed model is verified by experiments.