[Objective] The study aims to analyze the effect of bio-organic fertilizer on the supply of soil nutrient

the nutrient absorption by Bok choy

and vegetable biomass under the conditions of decreasing application of chemical fertilizer

and to provide theoretical basis for the practice of fertilizer-decreasing application. [Methods] We used the pot-test

with Bok choy as target species

to investigate the effect of bio-organic fertilizer and different amount chemical fertilizer mixtures on alkali-hydrolyzing nitrogen

rapidly available phosphorus

potassium on soil

and vegetable biomass and absorption of nitrogen

phosphorus

potassium by Bok choy. [Results] The bio-organic fertilizer could increase the supply of soil nitrogen

phosphorus and potassium in the limited period time if applying the mixture of both fertilizer. Furthermore

under the condition of the decreasing 15%～25% of conventionally chemical fertilizer application

the mixture fertilization technique did not affect the fertilizer supply of the soil

thus decreasing the non-point contamination of agriculture and stress of environment pollution. Bok choy growing test verified that under the decrease of 15%～25% of conventionally chemical fertilizer application

the mixture fertilization method did not reduce the biomass

and absorption of nitrogen

phosphorus

potassium of Bok choy

thus enhancing the utilization ratio of fertilizer. [Conclusion] Bio-organic fertilizer not only activate the soil available nitrogen

phosphorus

potassium

but also stabilize the supply.