This paper investigates the characteristics of turbulent structures in combined wave-current boundary layers based on the standard $ k $-$ \varepsilon $ model. Good agreements were found between the numerical results and experimental data of the time-averaged mean velocity profiles. Periodic variations of turbulence parameters within a wave cycle (i.e. vorticity magnitudes, TKE and TKE dissipation rates etc.) were observed. The vorticity magnitudes, TKE and TKE dissipation rates all decrease during the deceleration phase, reach their minimum values during the wave trough, increase during the acceleration phase and reach their maximum values during the wave crest. The variations of turbulent structures are very high in the near-wall regions (53% for TKE dissipation rates), and are quite low in the outer regions (3% for TKE dissipation rates). The wave-current boundary layer thickness increases (decreases) during the deceleration phase (acceleration phase). The model developed in this study has solved the existing issue of low accuracy in the near-bed region by previous models based on the “high Reynolds number methods”. The present model performs well in describing the physical process of turbulence variations under the effects of wave-current interaction. This can provide some guidance for the sediment transport in coastal areas, beach erosion prediction and developments of marine renewable energy.