A method of a circuit signal enhancement of a circuit board comprises the following steps: forming a first substrate body with a first signal transmission circuit layer and a second substrate body with a second signal transmission circuit layer; forming a first signal enhancement circuit layer and a second signal enhancement circuit layer on the first substrate body and the second substrate body; forming a third substrate body with a third signal transmission circuit layer and a fourth substrate body with a fourth signal transmission circuit layer on the carrier; separating the third substrate body and the fourth substrate body from the carrier; combining the first signal transmission circuit layer and the third signal transmission circuit layer through the first signal enhancement circuit layer; and combining the second signal transmission circuit layer and the fourth signal transmission circuit layer through the second signal enhancement circuit layer.