The invention relates to a system and a method of continuously removing impurities in solvent benzol in a caprolactam extraction process. The system comprises an impure benzene decanter which is connected to a first static mixer through an impure benzene delivery pump; the first static mixer is connected to a second static mixer; the second static mixer is connected to an efficient coalesce; the efficient coalescer is connected to a benzene rectifying tower through a coarse benzene delivery pump; and the efficient coalescer is also connected to a benzene stripping tower. The method comprises the following steps: separating heavy phases which are not dissolved in benzene in solvent benzol by means of decanting, initially separating free impurities in benzene and then feeding water-washed and alkaline-washed coalescer to remove a water phased; and feeding the separated benzene through the coalescer into the benzene rectifying tower for continuous rectification and impurity removal to remove recombinant impurities in benzene, and feeding the rectified and condensed benzene to a coarse caprolactam extraction section, wherein the extinction value of rectified benzene at 290nm is reduced from 0.25 to 0.1 or below, and the purity is greater than 99.98%.