Corn (Zea mays) Cob is rich source of cellulose, so this cellulosic material was utilized for ethanol production. The cellulosic material was pretreated with 1% H2SO4 at 1080 C Temp. by taking 1:5 proportion (solid : liquid). The pretreated cellulosic material was hydrolyzed with cellulase enzyme (conc. in FPU) at 600 C Temp., fermented by sacchromyces serevisiae 3090 at 300 C Temp. for 72 hrs. It was found that the hydrolysis time was increased at the interval of 12 hrs., the yield of reducing sugar and ethanol yield was increased i.e. 50.30% & 28.67 % resp. The particle size was inversely proportional to ethanol yield. Also substrate concentration should be minimize as such as possible for hydrolysis because the reducing sugar & ethanol yield (24.79% & 23.99%) had a similar variation trend with cellulase dosages varying from 10 to 30 FPU/ gm. substrate.