We present the concept of an on-line electric vehicle (OLEV) and its wireless power transfer mechanism and analyze the electromagnetic compatibility characteristics. As magnetic fields transfer 100kW of power to the vehicle, reduction of electromagnetic field (EMF) noise is a critical issue for protection of the human body. Also, with respect to electromagnetic interference (EMI) noise, a proper measurement method has not yet been established for this low frequency high power system. In this paper, low frequency magnetic field shielding methods and application of the shields to the OLEV system are presented. Furthermore, a standard low frequency magnetic field measurement is suggested as an EMI test.