Harmful algal blooms caused by Phaeocystis globosa have resulted in staggering losses to coastal countries because of their world-wide distribution.Bacteria have been studied for years to control the blooms of harmful alga,however,the action mechanism of them against harmful algal ceils is still not well defined.Here,a previously isolated algicidal bacterium Bacillus sp.LP-10 was used to elucidate the potential mechanism involved in the dysfunction of P.globosa algal cells at physiological and molecular levels.Our results showed Bacillus sp.