The diblock copolymers of methyl acrylate and perfluoroalkyl ethyl acrylate(FAEA) were synthesized by atom transfer radical polymerization (ATRP)．GPC

1H-NMR and fluorine-elementary analysis (F-EA) were used to study the structure of the block copolymers．To combine GPC with NMR and to combine GPC with F-EA were used to calculate the block length．It was found interestingly that the results of 1H-NMR showed a “temperature-dependent” feature．It means the relative ratios of MA block to FAEA block calculated from NMR were changed with measuring temperature．It might be caused by the formation of molecular association. Temperature and solvents can affect the degree of association. Therefore

1H-NMR and GPC can’t be used in quantitative analysis of the fluorinated diblock copolymer. To combine GPC with F-EA is suitable for the characterization of fluorinated diblock copolymers.