The invention discloses a plasticized polymer ionic liquid film and a method for selective separation of chromium (VI) through the same. The method comprises the steps that 1.5-2.5% of fatty amine and3.0-3.5% of polyvinyl chloride are taken as reaction raw materials to be subjected to reactive blending in 91.5-93.0% of an organic solvent, then 1.0-4.0% of a plasticizer is added, the solvent is removed through volatilization, the plasticized polymer ionic liquid film is prepared through acidification transformation, and selective separation of the chromium (VI) in chromium (VI) feed liquid isconducted through the plasticized polymer ionic liquid film under synchronous conducting of extraction and reverse extraction. A film preparation technology is simple, the using amount of a reagent issmall, and selectivity to the chromium (VI) is high; energy consumption is low in the extraction process, and secondary pollution is avoided; a film phase is not prone to leakage, a liquid film is stable in property, and the plasticized polymer ionic liquid film has the ability of continuous and repeated application; and the plasticized polymer ionic liquid film and the method can be applied to industrial application of selective removal of the chromium (VI) in the chromium-containing wastewater.