At present, all existent grid clients need install web browser or applications, so they are fat. While they can not almost support streaming media and their devices can not be accessed by grid services. Like thin-client (TC), flexible grid client (FGC) only requires clients to have basic input and display functions, so FGC is thinner than any kind of existent grid clients. However, FGC can support streaming media better than all existent grid clients and TC. In addition, FGC enables grid services to access client devices, such as printers, USB memory and scanner, which would be impossible with all existent grid clients and TC. As a result, grid computing would be more pervasive and more powerful with FGC, which elegantly combines the strengths of grid computing, thin-client computing and fat-client computing. Key words: grid computing; flexible grid client; thin-client computing; fat-client computing