Vertical mixing in the ocean affects the formation of water masses as well as the vertical distribution of nutrients and dissolved substances. this study is to investigate the effect of stability on the intensity of vertical transfer in the case of shallow and straitfied channel. It is found that the relation of the stability and vertical turbulent diffusion is given by K$sub$z/ = -${eta}$-(c+${eta}$) / ${alpha}$(E-1/${alpha}$) where K$sub$z/ and E denotes the vertical turbulent diffusion coefficient and stability, respectively. The empirical coefficients ${alpha}$, ${eta}$ and c depend on the magnitude of vertical components and stability, i.e., through thermocline intensity. The study indicates that the diffusivity of the surface mixed layer is (K$sub$z/)=300∼1,200$ extrm{cm}^2$/sec, the thermocline layer is (K$sub$z/)= 50∼200$ extrm{cm}^2$/sec and the cold layer is (K$sub$z/)=200∼600$ extrm{cm}^2$/sec based on near- minimum least-squares error estimates from the regression analysis. An important result of our study comes out that the model is in accordance with the general trends of the effect of stability on the vertical turbulent diffusion coefficients in the case of shallow and strongly stratified channel.