Through investigation and comparison of the methods of water purification, salvage and aeration were confirmed to be the most effective methods in treating the pollution in Lake Taihu. A solar water purification system was designed to achieve the effects of salvage and aeration. To collect algae as “salvage,” this purification system employed a combination of a water pump and filter screen. To increase the dissolved oxygen, the water pump lifted water and sprayed it into the air, and an air pump was equipped to inject oxygen bubbles into the water. After a one-year test at Lake Taihu, the effectiveness of this purification system was confirmed. It could effectively lower the levels of permanganate, NH3 4 NH+ / , and chlorophyll a and increase the level of dissolved oxygen in the lake water.