The invention discloses a liquid surface conditioning agent capable of improving the film-forming property of a phosphating film and a preparation method of the liquid surface conditioning agent capable of improving the film-forming property of the phosphating film. The liquid surface conditioning agent comprises the components, by weight, of 3%-9% of zinc nitrate, 1%-5% of calcium nitrate, 8%-15%of disodium hydrogen phosphate, 2%-4% of polyvinyl alcohol, 3%-7% of sodium alcohol ether sulphate, 2%-5% of trisodium pyrophosphate and 55%-81% of deionized water. The liquid surface conditioning agent is especially suitable for surface pretreatment of steel, aluminum and zinc before phosphating of zinc-calcium series and high in universality; crystallization active points in phosphating can beincreased, the grain size and binding force of the phosphating film are improved significantly, uniform growth of the phosphating film is facilitated, meanwhile, the phosphating temperature can be decreased, the phosphating time is shortened, the appearance quality of the phosphating film is improved, and corrosion resistance and abrasion resistance after phosphating are improved; and the preparation condition is gentle, and repeatability is high.