The invention relates to the field of waterproof materials, and specifically discloses a preparation method of a 
cement-based waterproof material. The preparation method comprises the following steps:mixing water, 
ethanol and a 
silane coupling agent, and carrying out 
ultrasonic oscillation, thus obtaining an oscillation solution; 
grinding sodium bentonite, adding and mixing the 
sodium bentonite powder in a 
sodium hydroxide solution, carrying out 
ultrasonic oscillation, taking a suspension solution, preheating and stirring, dropwise adding the oscillation solution, stirring, refluxing, cooling, filtering, and washing, thus obtaining a washing product; mixing 
butyl acrylate, 
methacrylic acid and 
methyl methacrylate, thus obtaining a 
mixed solution; mixing water, sodium 
hydrogen carbonate and a composite emulsifying agent, dropwise adding the 
mixed solution, heating, adding organosilicone and an initiator, heating, cooling and filtering, thus obtaining 
emulsion; mixing the washing product with deionzed water, dropwise adding an 
ammonium persulfate-
phosphoric acid water solution, stirring, adding the 
emulsion and a composite 
flame retardant, and uniformly stirring, thus obtaining a stirring solution; mixing the stirring solution, methyl 
hydroxyethyl cellulose ether and defoaming agent, stirring, adding 
cement under a stirring state, and uniformly stirring, thus obtaining the 
cement-based waterproof material.