Water networks with regeneration recycling, an important part of water system integration, can minimize freshwater consumption and wastewater discharge to a maximum extent, and so its integration method has received extensive attention. However, relative works only involves the water network with one-stage regeneration recycling. The cost of wastewater regeneration can be obviously reduced via multistage regeneration recycling with the same freshwater consumption and wastewater discharge. In this paper, how to construct the optimal water supply line with two-stage regeneration recycling is proposed. A graphical approach to determine targets of such water network is established, including the optimal freshwater flow rate, the optimal first stage regenerated water flow rate, the optimal second stage regenerated water flow rate, and the optimal regeneration concentration. Formulas to calculate these targets are deduced, and accordingly the improved problem table is presented to obtain these targets accurately. Based on the determined targets, the associated water network can be designed. Compared with the water network with one-stage regeneration recycling, the water network with two-stage regeneration recycling has significant advantages in terms of regeneration cost and using water according to the quality.