Silicon plays an important role in plant growth and resistance to adversity.In order to understand the effects of different concentrations of silicon on growth of sugar beet seedlings，thus laying a foundation for studying the regulation of silicon on plants，the indoor hydroponics experiment was conducted to study the morphological characteristics and physiological and biochemical changes of KWS1176 sugar beet varietiy，based on 3 mmol·L-1 Na+，under six concentration gradients of sodium silicate solution，including 0，0.3，0.6，1.2，2.4 and 4.8 mmol·L-1.The results showed that silicon significantly promoted the growth of sugar beet seedling，increased the height of sugar beet seedlings and made the leaves more erect than the control.At the same time，the appropriate concentration of sodium silicate reduced the malondialdehyde(MDA) content of sugar beet plants，and reduced superoxide dismutase(SOD)，catalase(CAT)，ascorbate peroxidase(APX) and peroxides enzyme(POD) activity.It is worth mentioning that among the four enzymes，CAT activity decreased most significantly.In addition，silicon promoted photosynthesis of sugar beet leaves.Stomatal conductance(Gs)，transpiration rate(Tr)，and net photosynthetic rate(Pn) were all increased under the action of sodium silicate，while the intercellular CO₂ concentration(Ci) showed a decreasing trend.Six indicators including dry weight，fresh weight and proline content etc.，were screened out by principal component analysis，which can be used as indicative indicators to evaluate the effect of sodium silicate on the morphology and physiological and biochemical characteristics of sugar beet seedlings.The comprehensive scores of the first and second principal components of sugar beet leaves and roots at different concentrations were calculated and ranked.When silicon concentration is 2.4 mmol·L-1，the growth and physiological indexes of sugar beet roots and leaves are the best.