With the enhancement of Grid application, Grid portal provides a unique interface for end-users to access distributed resources and are used widely in Knowledge Grid, e-Science, e-learning and e-business. A successful Grid portal relies on many factors. This paper focuses primarily on the design aspects of a successful Grid portal implementation. Ten questions of designing Grid portal are discussed in no particular order. The questions detail the key considering areas of Grid portal architecture, Grid portal contents, portal security, reusability, software design, management and programming test.