The present invention discloses a wide band test grab wire unit, a wide band test grab wire board and a wide band test device. The said wide band test grab wire unit, comprises the first, second and third test end, signal separator (14), the first, second and third switch, and the first, second and third interface end; the said wide band test grab wire board, comprises at least two wide band test grab wire units and internal test bus groups, and the forth, fifth and sixth switch, the said internal test bus group comprises internal inter-test bus, internal extra-test bus and internal secondary test bus; the said wide band test device, comprises at least one wide band test grab wire board, the eighth and ninth switch, test control module, and the external inter-test bus and external extra-test bus, the said buses are connected with the said test control module; the said wide band test device in present invention has simple structure and low cost, and N+1 copy function can be implemented easily between the ends inside the board, the reliability of communication can be further increased.