A reactive dye compound and preparation method and application thereof

A reactive dye compound, which is a compound of the following formula (I) or an alkali metal salt thereof:

• in formula (I):
• D1 and D2 are each independently the group of the following formula (a) or (b):
• in the above formulae (I), (a) and (b):
• R1 and R2 are each independently hydrogen, —COR7, C1˜C4 alkyl or C1˜C4 alkyl substituted by hydroxyl, sulfo or carboxyl, in which R7 is C1˜C4 alkyl, C2˜C4 alkenyl or —NH2;
• R3 is hydrogen, C1˜C4 alkyl, C1˜C4 alkoxy, carboxyl or sulfo;
• R4˜R6 are each independently hydrogen, C1˜C4 alkyl, C1˜C4 alkoxy or sulfo;
• X1 and X2 are each independently —SO2Y1, —NHCO(CH2)pSO2Y2 or —CONH(CH2)qSO2Y3, in which Y1˜Y3 are each independently —CH═CH2, —CH2CH2OSO3H or —CH2CH2Cl, p=1-3 and q=1-3.