Algal blooms are common world-wide in natural water bodies and pose a serious problem to the social economy and environment. It should be the first step to understand the mechanism of the occurrence and termination of algal bloom for controlling and decreasing their harmfulness. Algal bloom is also complicated ecological problem which include three phases of the occurrence and development and termination. The most work were focused on how to occur the algal bloom, and it was unclear why the algal bloom could be disappeared rapidly in large water bodies. The previous research results showed that algicidal bacterium which was in relation to the algal bloom existed the transformation from VBNC(Viable but non-culturable state) to culturable cell in aquatic environment, and this transforming was related to dynamic changes of algal population.