Composite algicide consisting of gemini surfactant and clay, and algae removal method

The invention discloses composite algicide consisting of gemini quaternary ammonium cation surfactant and clay solution and an algae removal method. The gemini quaternary ammonium cation surfactant has a structural formula in which R is C9-C20 alkyl, n is an integer from 2-10, and X is Br or Cl. The composite algicide not only has obvious algae removal effect, the dosage of the algicide is small and the algae removal efficiency is high. Meanwhile, the algae removal method is simple in operation, with the algae removal effect improved in aspects of dosage of the algicide and the algae removal time. Therefore, the algae removal method is more convenient and practical than the prior art.