This Research Paper provides a method for extracting a Leucaena leucocephala plant seed extract galactomannan. A method for extracting a Leucaena leucocephala plant seed extract, which includes 5 crushing seeds, followed by extraction with a solvent A water-soluble galactomannan having D-galactose (1-part) and D-mannose (3-parts) was isolated from Leucaena leucocephala. Hydrolysis of methylated seed gum furnished three methylated sugars 2, 3, 4, 6, - tetra-o-methyl-D-galactose, 2, 3, 6 – tri-o-methyl-D-mannose and 2, 3 di-o-methyl-D-mannose in the molar ratio 1.00:1.07:2.19. Partial acid catalyzed hydrolysis of the seed gum gave four oligosaccharides epimelebiose, mannobiose, galactosyl mannobiose and mannotriose along with the component sugars. Both periodate oxidation and methylation studies showed 25% of end groups. From the recent studies it is concluded that galactose unit in galactomannan only terminal positions. This Research Paper provides a method for extracting a Leucaena leucocephala plant seed extract galactomannan. A method for extracting a Leucaena leucocephala plant seed extract, which includes 5 crushing seeds, followed by extraction with a solvent A water-soluble galactomannan having D-galactose (1-part) and D-mannose (3-parts) was isolated from Leucaena leucocephala. Hydrolysis of methylated seed gum furnished three methylated sugars 2, 3, 4, 6, - tetra-o-methyl-D-galactose, 2, 3, 6 – tri-o-methyl-D-mannose and 2, 3 di-o-methyl-D-mannose in the molar ratio 1.00:1.07:2.19. Partial acid catalyzed hydrolysis of the seed gum gave four oligosaccharides epimelebiose, mannobiose, galactosyl mannobiose and mannotriose along with the component sugars. Both periodate oxidation and methylation studies showed 25% of end groups. From the recent studies it is concluded that galactose unit in galactomannan only terminal positions.