Preparation method of high-concentration PVA (polyvinyl alcohol) solution

The invention discloses a preparation method of a high-concentration PVA (polyvinyl alcohol) solution, which comprises the following steps: mixing 100 parts by mass of PVA, 0.01-0.3 part by weight of dissolving assistant and 80-300 parts by weight of solvent in a dissolving kettle; and introducing inert gas into the dissolving kettle, heating to 50-100 DEG C while keeping stirring, keeping the temperature for 0.5-2 hours, heating 95-195 DEG C while continuing stirring, and keeping the temperature for 1-3 hours to obtain the PVA solution. By combining pressurization, assistant addition and heating mode changes, the method disclosed by the invention can be used for preparing the PVA solution, of which the polymerization degree is 2800-4500, the alcoholysis degree is greater than or equal to 98% and the concentration is higher than or equal to 25%; and the method effectively shortens the time required by dissolution.