The invention relates to a post-processing method of a polyvinyl alcohol PVA gel fiber, which comprises the following steps: firstly, pre-stretching and fiber washing are carried out; secondly, a solvent is extracted under the negative pressure and the vacuum conditions; and thirdly, multi-step drawing, design finalizing and coiling steps are carried out. The extraction method is replaced by the vacuum extraction method, thereby removing the solvent in the gel-spinning fiber. The post-processing method has the advantages of simple process, high equipment utilization rate, low solvent residualrate, good fiber tensile property, no harmful gas, solvent recycling under complete sealing condition, reutilization after recycling, etc., and reduces the recycling cost.