Abstract: Soybean plants are very sensitive to boron deficiency. Under boron deficiency treatment, the patterns of change in growth, development and protective enzyme activity of soybean seedlings were investigated. In this study, Mengke 9 was used as a test material. At the soybean seedling stage, two treatments were set up of boron deficiency（B-） and full nutrition（CK）, respectively. Patterns of changes in photosynthetic physiological parameters, dry matter accumulation and protective enzyme activity were analysed in the different treatments, which performed correlation analysis. The results showed that soybean plant height, SPAD value, fluorescence value and dry matter accumulation were significantly reduced under boron deficiency treatment. Compared to the full nutrition treatment under T6（8 d） treatment time, soybean plant height was reduced by 12.54%, SPAD value by 27.33%, fluorescence value by 4.41% and dry matter accumulation by 28.25%. Soybean seedlings under B-deficiency treatment and allotrophic conditions, protective enzyme activities（SOD, APX, CAT and POD） showed an increasing and then decreasing trend with increasing stress time. Malondialdehyde（MDA） content showed a constant increase. Among these, the enzyme activities of the plant showed higher roots than leaves. The dry matter accumulation of soybean was positively correlated with plant height, SPAD value, fluorescence value and APX activity, positively correlated with SOD, CAT, POD activity, and negatively correlated with MDA content. These results showed that boron deficiency inhibited the growth and development of soybean seedlings. These results showed that boron deficiency inhibited the growth and development of soybean seedlings. In the early stages of stress, the activity of these protective enzymes increased, which is maintained normal growth of soybean.However, the activity of these enzymes decreased significantly with time under stress.