Two identical zigzag-shapes and an aluminum zigzag shape foil were combined as a slice testing piece. Each of the pieces was connected with AC. 110 V and AC. 12 V. The result indicated that the piece, whose tooth was 10mm wide with intervals of 15 mm, displayed an electromagnetic shielding effectiveness (EMSE) of 30 mG with the load current of AC. 110 V. The EMSE of another piece, whose teeth wide was 5 mm with intervals of 10 mm, was 20 mG in the load current of AC. 12 V. This result proved that samples were with EMSE under the alternating current.