From several aspects such as printed circuit board (PCB), grounding, shielding and filtering, the design measures to suppress the electric field radiation from electric equipments are introduced. With engineering examples, the issues radiation standard exceeding limit in tests are analyzed. The filtering principle of ferrite bead in the improved design is introduced in detail. The design method to choose appropriate ferrite bead based on tests data is proposed. The tests results show that the academic analysis is reasonable and the design measures are effective.