A signal switching device and a test system are disclosed. A printed wire which is connected with a test circuit can be selected flexibly according to actual situation, and a sufficient distance between adjacent tested printed wires/test printed wires which are used for transmitting a differential signal can be maintained, such that signal interference between the printed wires would not be easily generated. Signals can be effectively separated from each other, and thus the technical problem that signal interference would easily be generated between adjacent tested printed wires/test printed wires which are used for transmitting a differential signal can be solved.