In order to improve the security of OpenVPN technology, this paper introduces the VPN technology,based on SSL protocol,and then find the existing password algorithm of weak strength of the technology,put forward the method of high strength encryption algorithm which represented by ZUC has been internationally recognized to replace the original weak strength algorithm in OpenVPN,realised the call of ZUC algorithm by writing a custom engine including ZUC algorithm, and has the characteristics of low cost and high security. After the Sniffer Pro capture test and TCP / UDP debugging assistant data communications test, the results show that, data communication between the client and the server can be encrypted by zuc algorithm in order to achieve the purpose of communication security, and high strength encryption algorithm of the system, to a great extent, meet the such as government, military and financial security requirements in areas of higher demand, has a strong practical value.