A mechanical litchi picking process using a cut-clamp combined picker was modeled. A minimum clamping velocity model is required to ensure such a picker working reliably as well as to limit consumed energy. The picking process was sub-divided into seven stages. Three variables, namely the width of fiction head (D), the press on the clamping head(N) and fiction index between fruit branch( μk (v)) were chosen as independent variables. The output of modeling is the minimum cutting (or clamping) velocity. The model was verified using the experimental results of cutting and clamping by a simulated cut-clamp combined picker. The experimental results also showed if setting safety factor k=1.5, calculated velocities can ensure fruit branch be clamped firmly by the cut-clamp combined picker.