Biological slime treating agent for water treatment and preparation method of biological slime treating agent

The invention relates to a biological slime treating agent for water treatment and a preparation method of the biological slime treating agent. The biological slime treating agent comprises the following components in percentage by weight: 5-30% of 1-(2-thiocyano)ethyl-2-methyl-3-benzyl-5-nitroimidazole, 5-10% of N,N-bis(dodecyldimethyl)-3-oxa-1,5-pentadiammonium dichloride, 5-10% of dithiocyanomethane, 1-10% of isothiazolinone, 1-10% of organochlorine, 5-40% of a solvent and the balance of water. The preparation method of the biological slime treating agent is as follows: at room temperature, adding 1-(2-thiocyano)ethyl-2-methyl-3-benzyl-5-nitroimidazole, N,N-bis(dodecyldimethyl)-3-oxa-1,5-pentadiammonium dichloride and water into a reactor, adjusting the pH value to less than 6 with hydrochloric acid, adding an alcohol solvent, uniformly stirring, adding isothiazolinone and organochlorine and stirring until isothiazolinone and organochlorine are completely dissolved to obtain the biological slime treating agent. The biological slime treating agent has good bactericidal property, can be widely used in industrial circulating water treatment and especially can be suitable for controlling the breeding of bacteria such as SRB in an oily wastewater system of an oilfield.