Abstract: A dimononfluorotriazine（DMFT） reactive dye containing bis（monofluoro-s-triazine） groups was used to dyeing cotton fabric. The parameters influencing on the efficiency of dyeing on cotton have been discussed in detail，including dyeing temperature，concentration of salt and alkali and fixation temperature. When the dyeing temperature reached 90 ℃，the salt concentration was 70 g/L，fixation temperature set to 40—60 ℃ and alklai concentration reached 1－3g/L，the total fixation rate of DMFT dye was 87%. Compared with the analogous reactive dye containing bis（monochloro-s-triazine) groups（DMCT)，the total fixation rate of DMFT dye increased 13.5%. Cotton dyed with the reactive dyes containing different reactive systems has relatively the same fastness properties.