Through grid computing and cloud computing technologies, SCE (Scientific Computing Environment) integrates massive computing, storage and application resources. These resources are packaged as easy-to-use open APIs in RESTful web services. These APIs are used to develop terminal software for multi-disciplinary and cross-scenario. Around authentication and authorization issues among users, several services for open APIs, authentication and authorization are proposed and implemented in this paper. The proposed services provide single sign-on for several WEB communities by SCE accounts, support users to authorize terminal software that could access massive resources and personal private data in proxy mode, and also help administrators determine which open APIs a client could access. Atop the proposed services, all related people consisting of users, developers and administrators, no longer need to worry about and solve complex problems with authentication and authorization. What they need to pay much attention on are specific business logics and application scenarios for their interested areas. The proposed services have been applied to general computing portal, operation and management portal in national high-performance computing environment, and also WEB communities for computational chemistry, bioinformatics, etc. These examples show that the proposed services have achieved good performance and user experience.