Abstract: Grid data transfer protocol provides secure and reliable ability for transfers of large amounts of data,but the newest grid middlewarcGlobus Toolkit 4. 0 only suppose some commands and Application Program Interface. It is not easy to use GridFTP for common users. On the study of GridFTP, the paper designed and implemented one visual grid data transfer tool NGridFTP based on JavaCoG. NGridFTP realized upload and down of data, parallel data transfer, and third-party control transfer, etc. The experiment on large amounts of data shows that the parallel data transfer of NGridFTP has advantage over traditional transfer, but in parallel mode, adding the number of parallel TCP streams doesn't increase the transfer velocity.

Key words: Grid computing,GridFTP, Data transfer, NGridFTP