Abstract: Effects of culture condition,including nitrogen source,pH value and temperature on pentose(mainly xylose) fermentation by Pichia stipitis P2 were investigated.Both growth and xylose fermentation were as good with (urea) as a sole nitrogen source as with peptone as a sole nitrogen source.The optimum pH value and temperature range of the growth of Pichia stipitis P2 were 4.6-5.8 and 25-30℃,respectively.When cultural temperature was 25℃ and 35℃,the optimum pH value range of the xylose fermentation by P2 was 3.4-4.2 and 3.8-5.0,respectively.