The hop is rich in tannins meanwhile used as a conventional additive in beer industry, but other application is limited. This study investigated the tyrosinase inhibition activity of extracted hop tannins and the associated structure-function activity. The tannins were extracted and subjected to a gel permeation chromatography (GPC), a nuclear magnetic resonance (NMR) and an acid-cleavage coupled HPLC-ESI-MS/MS analysis to obtain the structural information of the tannins. Then tyrosinase inhibition kinetic assays, inductively coupled plasma optical emission spectrometer and antioxidant (ICP-OES), circular dichroism (CD) as well as molecular docking analysis were applied to investigate the inhibition mechanism. Furthermore, the intracellular inhibition ability of hop tannins was assessed with B16-F10 cells. The results indicated that, hop tannins were composed of (epi)catechin as extensional units and (epi)gallocatechin as terminal units and can be classified as prodelphenidins. The tyrosinase inhibition assays showed the hop tannin was 6.4 times more effective than hydroquinone, meanwhile it inhibited the tyrosinase through competitive-noncompetitive mixed way. The tannins were found to bind on the surface of tyrosinase via forming hydrogen bonding and consequently changed the secondary structure of tyrosinase. The fluorescence and antioxidant assay indicated the tannin had both copper ion chelating and antioxidant ability which may also contribute to the inhibition. The intracellular inhibition analysis showed activity of tyrosinase were reduced by 66.67% and melanin production were found reduced by 34.50% while 10uM hop tannins were applied. These results indicated that, the hops are not only important in beer industry, the hop tannins can be also applied as whitening agents in cosmetic industry.