Abstract: The sugar beet cultivars KWS9167 was used as materials using the LCpro-SD in this study.The effects of different nitrogen levels（0,50,100,150 and 200 kg/hm2）were studied on dynamic changes of photosynthetic characteristic, in order that comparing the beet photosynthetic characteristics under different nitrogen levels and the relationship between the yield and quality. The results showed that： chlorophyll content, photosynthetic rate（Pn）, transpiration rate（Tr） and stomata conductance（Gs） were all expressed in single peak curve. From the foliage rapid growth stage to root enlargement growth stage（June 20 to July 11）, during the period the indicators were at a higher level, which indicated that the sugar beet growth at the vigorous stage. In the range of 0 ~150 kg/hm2, chlorophyll content, SPAD and photosynthetic rate increased with the increase of nitrogen application and excess nitrogen level growth effect was not obvious. The correlation between the chlorophyll content, SPAD and sugar beet yield were significantly positive. The correlation between photosynthetic rate and yield was significantly positive.