Semiconductor core fiber has attracted more and more attention due to its special photoelectric characteristics. The drawing of the semiconductor core fiber is more complicated than the conventional silica fiber due to the difference in properties between the core and the cladding material. In this paper, the Ge-core fiber is taken as the research object, and the dynamic drawing process of the Ge-core fiber is simulated by the finite element method. The difference in flow rate between the core of germanium and the cladding of silica, and the effect of different fiber drawing speeds on this flow rate difference are studied. The simulation result shows that significant difference of the core and cladding flow rate is at the position of the neck-down region of the preform, and the different drawing speed has different effects on the flow rates of the Ge-core and the silica-cladding of the preform.