A low-molecular-weight glycosaminoglycan derivative or a pharmaceutically acceptable salt thereof, wherein: monosaccharide compositions of the low-molecular-weight glycosaminoglycan derivative comprise hexuronic acid, hexosamine, deoxyhexamethylose and the sulfate forms of those monosaccharides; wherein,the hexuronic acid is D-glucuronic acid and Δ 4,5 -hexuronic acid (4-deoxy- threo -hex-4-enepyranosyluronic acid), the hexosamine is acetylgalactosamine (2-N-acetylamino-2-deoxy-D-galactose) or a terminal reduction product thereof, the deoxyhexamethylose is L-fucose; based on molar ratio, the ratio of each monosaccharide and -OSO 3 - in the low-molecular-weight glycosaminoglycan derivative is hexuronic acid: hexosamine: deoxyhexamethylose: sulfate group =1: (1±0.3): (1±0.3): (3.0±1.0); in the hexuronic acid, based on molar ratio, the percentage of Δ 4,5 -hexuronic acid is not less than 2.5 % of the total hexuronic acid; the low-molecular-weight glycosaminoglycan derivative has a weight average molecular weight (Mw) of 3kD-20kD; the low-molecular-weight glycosaminoglycan derivative has a polydispersity index of between 1.0 and 1.8, further the low-molecular-weight glycosaminoglycan derivative is a mixture of the homologous glycosaminoglycan derivatives having a structure of Formula, in Formula: n is an integer with average value of 2-20; -D-GlcUA-β1-is - D-glucuronic acid-β1-yl; -D-GalNAc-β1- is -2-deoxy-2-N-acetylamino-D-galactose-β1-yl; L-Fuc-α1- is -L-fucose-α1-yl; R is -OH or -OSO 3 -; R' is -OH, C1-C6 alkoxy, or C7-C10 aryloxy; R 1 is a group shown in Formula or, and in said mixture, based on molar ratio, the ratio of the compounds that R 1 is Formula to the compounds that R 1 is Formula is not less than 2:1; wherein, ΔUA-1- is Δ 4,5 -hexuronic acid-1-yl (4-deoxy- threo -hex-4-enepyranosyluronic acid-1-yl), R and R' are defined as above; R 2 is a group shown in Formula or, wherein, R and R' are defined as above; R 3 is carbonyl, hydroxyl, C1-C6 alkoxy, C1-C6 alkoxycarbonyl, C6-C12 aryl, substituted or non-substituted five or six membered nitrogen-containing heterocyclic group, or -NHR 4; wherein R 4 in -NHR 4 is substituted or non-substituted straight or branched chain C1-C6 alkyl, substituted or non-substituted C7-C12 aryl, substituted or non-substituted heteroatom-containing heterocyclic aryl. monosaccharide compositions of the low-molecular-weight glycosaminoglycan derivative comprise hexuronic acid, hexosamine, deoxyhexamethylose and the sulfate forms of those monosaccharides; wherein,the hexuronic acid is D-glucuronic acid and Δ 4,5 -hexuronic acid (4-deoxy- threo -hex-4-enepyranosyluronic acid), the hexosamine is acetylgalactosamine (2-N-acetylamino-2-deoxy-D-galactose) or a terminal reduction product thereof, the deoxyhexamethylose is L-fucose; based on molar ratio, the ratio of each monosaccharide and -OSO 3 - in the low-molecular-weight glycosaminoglycan derivative is hexuronic acid: hexosamine: deoxyhexamethylose: sulfate group =1: (1±0.3): (1±0.3): (3.0±1.0); in the hexuronic acid, based on molar ratio, the percentage of Δ 4,5 -hexuronic acid is not less than 2.5 % of the total hexuronic acid; the low-molecular-weight glycosaminoglycan derivative has a weight average molecular weight (Mw) of 3kD-20kD; the low-molecular-weight glycosaminoglycan derivative has a polydispersity index of between 1.0 and 1.8, further the low-molecular-weight glycosaminoglycan derivative is a mixture of the homologous glycosaminoglycan derivatives having a structure of Formula, n is an integer with average value of 2-20; -D-GlcUA-β1-is - D-glucuronic acid-β1-yl; -D-GalNAc-β1- is -2-deoxy-2-N-acetylamino-D-galactose-β1-yl; L-Fuc-α1- is -L-fucose-α1-yl; R is -OH or -OSO 3 -; R' is -OH, C1-C6 alkoxy, or C7-C10 aryloxy; R 1 is a group shown in Formula or, and in said mixture, based on molar ratio, the ratio of the compounds that R 1 is Formula to the compounds that R 1 is Formula is not less than 2:1; wherein, ΔUA-1- is Δ 4,5 -hexuronic acid-1-yl (4-deoxy- threo -hex-4-enepyranosyluronic acid-1-yl), R and R' are defined as above; R 2 is a group shown in Formula or, wherein, R and R' are defined as above; R 3 is carbonyl, hydroxyl, C1-C6 alkoxy, C1-C6 alkoxycarbonyl, C6-C12 aryl, substituted or non-substituted five or six membered nitrogen-containing heterocyclic group, or -NHR 4; wherein R 4 in -NHR 4 is substituted or non-substituted straight or branched chain C1-C6 alkyl, substituted or non-substituted C7-C12 aryl, substituted or non-substituted heteroatom-containing heterocyclic aryl.