The invention discloses a linen 
fiber modification method, in particular to a linen 
fiber graft aminization modification craft, belonging to the technical field of printing and 
dyeing, which is characterized in that the linen 
fiber is selectively oxidized with oxidant solution such as 
sodium periodate, and oxidation linen fiber is obtained; the surface 
aldehyde group of the oxidation linen fiber is reacted with the surface amino of amine-terminated overbranched compound and the 
quaternary ammonium salt, which are combined by 
covalent bond, and the graft aminization linen fiber is prepared; the abundant amino, imino group and 
quaternary ammonium branched chain are introduced on the surface of obtained fiber, which can increase significantly the 
dyeing performance of linen fiber, and simultaneously increase the 
pliability softness, hygroscopicity and antibacterial performance of linen fiber. The linen fiber modification method has the advantages of fast 
reaction rate, high graft efficiency, good fastness, convenient and easy operation, realization of non-salt 
dyeing for linen fiber after modification treatment, environment protection, simplified normal dyeing craft and wide potential application.