In the light of problem of small water environmental capacity and bad water quality of urban landscape water body in water-deficient city, the paper proposed a method that use dynamic control model of water environmental capacity and total content to conduct water quality management. Taking Bolong urban landscape lake in Tianjin as a case study,water environmental capacity calculation results of Bolong urban landscape lake showed that natural water environmental capacity cant not satisfy the requirement the total pollutant input, but if water purification system operates according to design patterns, which can produce more remaining water environmental capacity. Using the model to conduct dynamical control for total water environmental capacity in Bolong urban landscape lake and when the water quality standard reach class IV, the water load of water purification system can be reduced by 46.1 percent. The water environmental capacity can be fully used.