The invention relates to a clamp sensor screening method, characterized in adopting at least two screening layers. And the clamp sensor comprises a probe casing and an iron core, where the iron core is arranged in the probe casing, and it is characterized in that at least two screening layers are arranged between the iron core, that the probe casing, each screening layer corresponds to a different or the same ground, and that a filling silica gel is arranged between the screening layers. The advantage lies in that the invention can measure weak electric signals. |