Abstract: Effect of different boron levels on the occurring rate of onion-type garlic and its change of physiological-biochemical index were studied by nutrient solution. The results showed that the onion-type garlic can be induced when boron content were 0 or 1.5 mg · L-1，as well as fresh and dry weight of bulb decreased at these concentrations. However，when the boron content were 0.5 and 1.0 mg · L-1 in nutrient solution the onion-type garlic can be prevented. Compared with normal plants，the onion-type garlic senescence was slower. During the late growing stage of bulb，the boron content，photosynthetic pigment contents，photosynthetic parameter（Pn，Tr，Gs）and the activity of protection enzyme（POD，CAT，SOD）in leaf were higher than the normal plants which in the same condition as the onion-type garlic. It can be respectively increased the content of soluble sugar，soluble protein and free amino acids which include in leaf laminas and pseudostems of onion-type garlic，when the boron in nutrient solution were 0 mg · L-1 and 1.5 mg · L-1. And on these concentrations，the content of soluble sugar，soluble protein and free amino acids in bulb reduced by 30.45% and 51.99%，152.26% and 258.34%，82.01% and 56.09%.

Key words: garlic, onion-type garlic, boron, physiological characteristics