Provided are a device, a differential signal line processing method and a differential signal line processing apparatus. The device includes a first component and a second component; the first component and the second component perform signal transmission via multiple sets of differential signal lines; the device further includes at least one common-mode filter, each common-mode filter of the at least one common-mode filter being serially connected between the first component and the second component via one set of differential signal lines, and a group delay of the each common-mode filter being adopted for adjusting a delay of signal transmission on the one set of differential signal lines connected to the common-mode filter.