Electromagnetic (EM) wave is a form of energy that is emitted and absorbed by charged particles. EM pollution becomes the fourth pollution next to air, water and sound pollution. Current technologies and all electronic devices are the source of this pollution, which can cause cancer, thermal, hereditary problems. These pollutions are common in electric vehicles in which extremely low frequencies (1 – 300 Hz), radio frequencies (100KHz – 300 GHz) are generated from sensors, electronic security systems, charging system, car network, GPS, Bluetooth, Wi- Fi and other control systems in side electric vehicles that cause health problems at long time exposure for passenger and drivers. To take part in solving this problem pine wood biochar (PWB)/high density polyethylene (HDPE) composites with good electromagnetic shielding effectiveness were successfully fabricated using melt blending and hot compression molding for electric vehicle battery and high power traction component shielding. High temperature (620 o C) pyrolyzed PWB fabricated with large pore sizes, pore volumes, high specific surface areas and higher carbon contents compared to other biochars (coffee husk, sugar cane bagasse and maize cob) that enables it to have good electrical conductivity, thermal stability, and electromagnetic shielding properties when combined with HDPE plastic. Different weight percentages (10, 20, 30 and 40 wt. %) of PWB had been melt blended and molded with HDPE, and characterized experimentally. The results showed that PWB enhance the electrical conductivity, thermal stability and EMI shielding effectiveness (SE) of HDPE significantly. In particular, the PWB/HDPE composite with 30 wt. % PWB exhibited the highest thermal conductivity of 2.219 W/mK, and 40 wt. % PWB composites achieved the highest electrical conductivity of 4.67 x 10 -7 S/cm and EMI SE of 44.03 dB (99.99% attenuation) at 2.1 GHz. These good results show a new, environmentally available, cost effective, scalable ways to use waste biomasses and recycled high density polyethylene plastic wastes in polymer composites for EMI shielding applications. Keywords: Biochar, HDPE, Composites, Thermal stability, Electrical conductivity, Shielding effect, Electromagnetic