This study explained the importance of some microorganisms in camel ruminal fluid as a source of cellulase enyzme. Different strains of cellulolytic bacteria were isolated as Bacteroides ruminicola, Bacteroides succinogcnes, Butyrivibrio fibrisolvens, Ruminococcus flavefaciens and Ruminococcus albus. Pure culture of cellulolytic bacteria Ruminococcus albus was experimented for studying factors which affect its celluloytic activity. Increasing in bacterial count resulted in the decrease of remained cellulose concentration in cellulose digestion broth. The activation of cellulase enzyme to digest cellulose occurred until it was saturated and by increasing concentration of substrate, the activation decreased gradually till it became constant. The optimum cellulolytic activity of Ruminococcus albus was performed at pH 7.0 and when incubated at 39°C for 72 hours. Addition of ampicillin and gentamicin caused significant inhibition of this bacterium to digest cellulose.