The formation of algal bloom requires a huge amount of nitrogen and phosphorus nutrients, higher water temperature and slow water flow velocity. When these conditions are ready, the cyanobacterial cells will reunite and float up, and finally become cyanobacterial bloom on the surface of water, leading to the death of other organisms in the water. In this study, algal bloom was taken as source domain and cancer as target domain. By mapping algal bloom to the cancer in human body, a series of analogical mapping was conducted between water temperature and heat-toxicity, water flow velocity and qi-blood circulation, the resuscitation of cyanophyta and recurrence of cancer, trying to discuss the pathogenic mechanism of cancer caused by algal bloom, so as to trigger some beneficial thoughts.