Cold-soluble polymer as well as preparation method and application thereof

The invention provides a cold-soluble polymer as well as a preparation method and application thereof. The preparation method comprises: S1, dispersing a saponified polymer in a good solvent to obtain a polymer dispersion liquid, the polymer being polyvinyl alcohol or an ethylene-vinyl alcohol copolymer, and the saponification degree of the polymer being 94-100 mol%; s2, precipitating the polymer dispersion liquid by using a precipitant to obtain a first polymer wet solid, the first polymer wet solid comprising liquid molecules entrained in the polymer, and the liquid molecules comprising a good solvent and the precipitant; s3, liquid molecules in the first polymer wet solid are extracted through an extraction agent, an extracted wet solid is obtained, the extraction agent is selected from precipitants, the volatilization speed of the extraction agent is higher than that of the precipitants used in the step S2, and 90% or above of the extraction agent remaining in the extracted wet solid is lower alkane; and