The effects of different phosphorus (P) levels on yield，photosynthetic characteristics and quality of garlic were studied by using hydroponic experiment.Six different P concentrations at 0，0.5，1.0，1.5，2.0，2.5 mmol/L were designed.The results indicated that the fresh weight of bulb，the transverse diameter of bulb，the fresh weight of bolt，the bolt diameter and the bolting rate were increased at firstly and then decreased with the increasing of P concentrations，these yield related indexes under the treatment of 1.5 mmol/L were the highest，which were increased by 891%，177%，283%，415% and 519% respectively compared to the treatment of 0 mmol/L.The P content in bulb and bolt were highly significantly correlated with the increasing of P concentrations.The pigment contents and photosynthetic parameters (Pn，Tr，Gs) of leaf were the highest at 1.5 mmol/L P concentration，and they were decreased at below or above 1.5 mmol/L P.The quality index in bulb and bolt were also increased at firstly and then decreased with the increase of P concentrations.Among them，the maximal value of vitamin C，soluble sugar，free amino acid and soluble protein contents appeared at 1.5 mmol/L P concentration，while allicin content at 2.0 mmol/L.Thus it can be seen that，the 1.5 mmol/L P concentration was the best treatment to garlic under the condition of this study.