In order to provide high quality information security service in public network,a new scheme is developed for constructing a secure Virtual Private Network(VPN).In this scheme,security protocols are separated from operating system and integrated into the network equipment—safe Ethernet card.When a program makes use of network equipments,the protocols cannot be bypassed.So the scheme can be used in security communication and can prevent active attack.The hardware platform and inner software structure of the Ethernet card are introduced,and the multiple access manners of the VPN are discussed.A method accessing ADSL in VPN based on PPPoE in the card is presented,which is validated to achieve the expected purpose.