The spatial distribution, temporal changes of water transparency and relationship between transparency and turbidity,suspended substance, chlorophyll-a, radio of total nitrogen and total phosphate, pH were analyzed based on monthly (May-October)monitoring data in Lake Wuliangsuhai from 2006 to 2008. The results indicated that the water transparency in Lake Wuliangsuhai in2006 to 2008 ranged from 0.33m to 1.62m with a mean value of 0.93m, and the distribution trend of transparency took on increasingfrom the northeast to the southwest. The correlation analysis results showed that turbidity and the amount of suspended substancesare two significant factors that affected the transparency. Their regression functions can be represented as SD=1.489x ^-0.471 (R=0.83,N=100, P<0.0001) and S^1/4 =-3.948lnSD+12.055 (R=0.65, N=100, P<0.0001) respectively.