Many nutraceutical and pharmacological properties of mushrooms are ascribed to beta-glucan. It is, therefore, important to characterise these compounds. The present study aims to analyse and characterise glucan extracted from fruiting body of oyster mushroom. Glucan was purified and hydrolysed to remove proteins, fibers, and fats and was characterised by different techniques. In crude and hydrolysed glucan, peak was scanned by UV/VIS spectroscopy at 280 nm which indicated the presence of impurity of protein, whereas in purified glucan, peaks at 190 nm, 290 nm represented the presence of glucan with the exclusion of peak at 280 nm. The FTIR analysis of the glucan revealed the presence of different functional groups such as O-H (3753.49-2976.12 cm(-1)), C-H (2357.76-2326.84) and C=O (1562.72-1500.0 cm(-1)) which are unique parameters of the given sample X-ray diffraction angles in crude (20, 25, 35 and 400), purified (20 theta) and hydrolysed glucan (25 theta), showed that crude oyster mushroom has impurity. SEM analysis showed that crude oyster mushroom surface was rough, and of purified and hydrolysed were smooth to some extent. TGA analysis of sample showed that thermal stability of glucan decreased to some extent but resulted in the fragmentation of the glucan to increase its potential applicability in food supplements.