This experiment was conducted to study the effects of two different dosage forms of phytase (powdery and granular) on laying performance, egg quality and bone quality of laying hens. A total of 1 440 30-week-old Lohmann pink-shell hens were randomly assigned to 4 treatments with 6 replicates each and 18 hens in each replicate. Treatment Ⅰ was the positive control group (PC); treatment Ⅱ was the negative control group (NC) for which diet was formulated on the basis of PC diet with Ca and AP levels decreased to 3.23% and 0.24% (1 to 5 weeks) or 3.23% and 0.19% (6 to 10 weeks), respectively; diets for treatments Ⅲ and Ⅳ were supplemented with powdery or granular phytase based on NC diet (300 U/kg). The experiment lasted for 10 weeks. The results showed that feed intake and bone ash were significantly decreased (P<0.05), while egg broken ratio (6 to 10 weeks) was significantly increased (P<0.05) in NC group, but there were no significant differences in egg production, egg weight and egg quality of laying hens in NC group (P>0.05), and there were no significant differences in laying rate, egg quality, and average egg weight between powdery and granular phytase (P>0.05). Dietary supplementation with powdery phytase could significantly increase the phosphorous content of bone ash (P<0.05), and dietary supplementation with granular phytase could significantly decrease the cracked and broken egg ratios in 6 to 10 weeks (P<0.05). In conclusion, dietary supplementation with phytase in low phosphor diet can improve average daily feed intake and bone ash of laying hens without damaging egg quality. There is no difference in laying performance, egg quality and bone quality between powdery and granular phytase. ［Chinese Journal of Animal Nutrition, 2010，22（5）:1374-1381］