A simple algal ecological model is established based on the current knowledge on the Meiliang Bay, Taihu Lake. Combining with the ecological simulation results and the field data，we analyze the harness ways of blue algal bloom concerning pollution control and dredging engineering.The simulation results show that, the reduction of the total nitrogen and the total phosphorus input will bring out greatly the decreasing of blue algal bloom and the reduction effect of the total phosphorus is greater than that of the total nitrogen. To reduce the bloom， the simulation result shows that it is not an effective way to reduce the sledge releasing rate. Once the water pollution control target is satisfied the level of water bloom will decrease to the very low level. However, to optimize the achievements, it is necessary to consider both the total amounts of nitrogen and phosphorus and their ratio by the use of economical and bcncficial analysis. From the simulation results and the updated investigation data of the sledge distribution in Taihu Lake, we conclude that it is very limited for algal harness to proceed the dredging engineering. Despite of this, some ways are put out to proceed the engineering while the aquatic bio-organism should be protected reasonably.