Based　on　the　theory　and　method　of　driver　workload,　two　mountainous　expressway　sections　were　chosen　for　real-vehicle　testing　with　a　random　sample　of　27　drivers.　The　testing　vehicles　are　passenger　car　and　truck.　Dynamic　GPS,　electrocardiogram　equipment　and　ophthalmotrope　systems　were　employed　for　real-time　measurements　of　vehicle　location　and　parameters　of　driver　workload.　In　this　research,　the　classification　standards　of　combination　of　vertical　and　horizontal　curves　were　obtained,　and　the　regression　model　between　driver　workload　degree　and　road　alignment　index　was　established.　In　addition,　the　regression　model　was　proved　through　inspection　of　accident　numbers.　Research　results　can　provide　technical　support　for　classification　of　combination　of　vertical　and　horizontal　curves　and　its　safety　design,　operation　and　management.