The effect of supplemental microbial phytase and non - phytate phosphorus(NPP) levels on layer productivity and nutrient digestibility were conducted in 640 21 weeks - old HyLine brown layer for 12 weeks. Supplemented phytase levels were 0, 300, 500 and 1,000 DPU/kg diet. NPP levels were adjusted with tricalcium phosphate(TCP), which were 0(0.11% NPP), 0.5(0.20), 1.0(0.29) and 1.5%(0.38). ME, CP and Ca levels were maintained at 2,800㎉/kg diet, 16% and 3.5%, respectively. Egg production was increased with phytase compared to without phytase(P〈0.05). Increasement of egg production was higher latter of experimental period. Egg production was not different to phytase levels. Egg production in TCP levels were increased in above 0.5% compared to 0% TCP. Difference of egg production by TCP was higher after 6 week. Especially, egg production to supplemental phytase was higher in 0% TCP. Egg weight was not different to phytase and TCP levels. Egg mass was increased with phytase compared to without phytase, but not difference significantly. There was similar to phytase levels. Egg mass in TCP group was increased in TCP supplementation(P〈0.05). Feed intake was not different in phytase levels, and greater with increasing TCP levels(P〈0.05). Feed conversion was improved with phytase(P〈0.05), and not difference in TCP levels. All of nutrients digestibility tended to improve with phytase, P(P〈0.05), especially. There were not different among phytase levels. The effect of adding phytase was higher in low phosphorus diets compared normal levels. Eggshell breaking strength and eggshell thickness also improved in added phytase(P〈0.05). Tibial ash and P content were slightly increased with phytase, and Ca content also was higher(P〈0.05) compared without phytase. We concluded that supplemental phytase in low phosphorus diet was showed to increase laying performance, feed efficiency, nutrients digestibility, egg quality, and bone development. Phytase supplementation was able to compensate for low NPP diet. We also thought optimum phytase level is 300 DPU, and can decrease NPP supplementation adding phytase in later diet.