Abstract: Further increasing the yield and sugar content of sugar beet is significant for the development of sugar beet production, sugar industry and increasing farmers’income. In this study, the photosynthetic characteristics of different varieties of sugar beet were compared during the whole growth period. The results showed that: there was significant difference of SPAD, photosynthetic rate, stomata conductance, intercellular CO₂ concentration and transpiration rate in different sugar beet genotypes during the growing period. In sugar accumulation stage, SPAD value of high-yielding varieties was lower than that of high sugar varieties. In root and sugar growth stage, photosynthetic rate of high- yielding varieties was higher than that of high sugar varieties. In the seedling stage, intercellular CO₂ concentration of high-yielding varieties was lower than that of high sugar varieties, intercellular CO₂ concentration of high yield varieties in sugar accumulation period was higher than that of high sugar varieties. In the foliage rapid growth stage, stomata conductance of high-yield varieties was lower than that of high sugar varieties. The transpiration rate of high-yield varieties in foliage rapid growth stage and sugar accumulation period was lower than that of high sugar varieties.