In　order　to　mitigate　driving　fatigue　and　reduce　traffic　accidents,　a　study　on　the　variation　law　of　electroencephalograph　(EEG)　and　electrocardiograph　(ECG)　with　driving　time　was　made　in　a　driving　simulator.　The　correlation　between　the　original　data　of　EEG　and　ECG　and　each　indicator　for　assessing　driving　fatigue　was　analyzed,　and　the　overall　index　of　driving　fatigue　was　determined　by　principal　component　analysis.　An　orthogonal　experiment　was　carried　out　in　the　driving　simulator　cab　to　validate　the　effectiveness　of　sound　stimulus　as　a　countermeasure　against　driving　fatigue.　The　results　show　that　drivers　in　fatigue　have　an　alerting　reaction　to　the　single　sound　stimulus;　stimulation　interval　and　sound　intensity　have　a　significant　influence　on　driving　fatigue,　but　stimulation　time　and　sound　frequency　have　a　weak　influence　on　driving　fatigue.　The　best　effect　in　alleviating　driving　fatigue　was　achieved　when　the　sound　intensity　was　70　dB,　the　sound　frequency　5800　HZ,　the　stimulation　time　7　s,　and　the　stimulation　interval　30　s.