Katatatic winds are important in pollutants transportation and ventilation for urban settlements in mountainous regions. Most of the theoretical analysis of slope flow is confined on bare slope, although the mountains are covered by heterogeneous forest canopies. To fill this gap, a new theoretical model for slope flow by taking the forest canopy into account was developed in this paper. Classical Prandtl slope flow model is implemented above the canopy while the canopy flow model is applied within the uniform canopy. The coupling of the two models is formulated at the canopy top. The influence of atmospheric stability and slope inclination is also investigated.postprintThe 7th International Conference on Urban Climate, Yokohama, Japan, 29 June-3 July 2009