A bridging board configured for connecting a processor with a hard disk backboard includes a first signal connecting apparatus, a second signal connecting apparatus, a plurality of duplexer and a signal conditioner. The first signal connecting apparatus is electronically connected to the processor. The second signal connecting apparatus electronically connected to the hard disk backboard. Each duplexer has an input terminal electronically connected to the first signal connecting apparatus, and two output terminals electronically connected to the second signal connecting apparatus to allow the processor to communicate with the backboard via the bridging board. The signal conditioner is electronically connected between the first signal connecting apparatus and the second signal connecting apparatus to amplify signals transmitted from the processor to the hard disk backboard.