Magnetic shielding is an important design for all electrical system. This is especially important to today's electric mobility because nearly all traction drives are using electric motor and they are driven by high frequency carrier wave from 1kHz to 100kHz. The interference to the signal system of vehicle control unit should cost a damaging effect. Besides the use of filter of metal shielding, a new plastic based magnetic shielding technique is introduced that provides a flexible shielding for the EMI isolation. The new material is especially useful for transportation system because they are light weight, non-brittle, lower cost and prominent performance in high frequency. 