The effect of steam on treatment of bagasse(particle size of 0.15 mm) is well studied by conducting using high pressure steam(15 psi, 121°C) and the pretreatment time is varied form 5 to 20 mins. A maximum reduction of 0.00% of cellulose, 15.45% of hemicellulose and 9.82% of lignin were obtained for a treatment time of 20 min. The total sugar content is increased by 4.38% due to the possible conversion of cellulose polymers into monomers and dimmers. The cellulose content is not changed even when the steam treatment time increased upto 20 minutes and also the hemicellulose and lignin content is significantly reduced by about 15.45 and 9.82% respectively. Generally cellulose(6-carbon) sugars would not degrade at this steam pressure and temperature