Abstract: The Yin-Yang-grid Unified Model for the Atmosphere (YUNMA) is a non-hydrostatic atmospheric model developed on the quasi-uniform Yin-Yang grid. In order to improve the model performance in simulating atmospheric boundary-layer processes, a scale-aware Mellor-Yamada-Nakanishi-Niino (MYNN) boundary-layer parameterization scheme is implemented into the YUNMA model instead of the original MRF scheme. With the constraint of prognostic turbulent kinetic energy (TKE) and the scale-aware parameterization of both local and non-local turbulences, turbulent structure and the distribution of physical variables are improved in the boundary layer. A numerical simulation on a sea fog process over the Yellow Sea on 26 February 2014 shows that the YUNMA model with the MYNN scheme reproduced the proper spatio-temporal variation of the sea fog with the Threat Score increased by 0.48. The root mean square error of dew point temperature was decreased by 0.3?1.8°C below 700 hPa. The MYNN scheme enhanced the feature of low-level vertical turbulent transport and the structure of temperature and moisture, and improved the temperature decrease and moisture increase associated with turbulences in the Yellow Sea region. Outstanding ability in representing subgrid-scale turbulent mixing and vertical exchanges is revealed. Implementation of the MYNN scheme obviously improved the performance of the YUNMA model in simulating the boundary-layer processes, which can be used for reference in atmospheric model developments.