A chip on film (COF) trace routing method for EMI reduction includes: providing a flexible circuit board; mounting a chip that has a first signal pad, a second signal pad and a ground pad on the flexible circuit board; and forming a first signal trace, a second signal trace, a first ground trace and a second ground trace on the flexible circuit board. The first signal trace and the second signal trace are electrically connected to the first signal pad and the second signal pad respectively. The first ground trace and the second ground trace are both electrically connected to the ground pad. The first signal trace and the second signal trace are disposed between the first ground trace and the second ground trace. The first ground trace and the second ground trace are immediately adjacent to the first signal trace and the second signal trace respectively.