Stokes drift is the main source of vertical vorticity in the ocean mixed layer.In the ways of Coriolis-Stokes forcing and Langmuir circulations, Stokes drift can substantially affect the whole mixed layer.A modified Mellor-Yamada 2.5 level turbulence closure model is used to parameterize its effect on upper ocean mixing conventionally.Results show that comparing surface heating with wave breaking, Stokes drift plays the most important role in the entire ocean mixed layer, especially in the subsurface layer.As expected, Stokes drift elevates both the dissipation rate and the turbulence energy in the upper ocean mixing.Also, influence of the surface heating, wave breaking and wind speed on Stokes drift is investigated respectively.Research shows that it is significant and important to assessing the Stokes drift into ocean mixed layer studying.The laboratory observations are supporting numerical experiments quantitatively.