The flowing behavior of liquid slag has an important effect on the heat efficiency, recovery ratio of valuable metals and life span of the electric cleaning furnace. The velocity procedure using “k-ε” model was developed under the cylindrical coordinate system. The procedure is used to calculate the velocity field of molten slag. The forces acting on molten slag were analyzed. The calculating method of electromagnetic force was described. The discrete equations, which were solved by using SIMPLE algorithm, were generated by means of interlace grids and control volume. The boundary layers near the solid wall were treated as wall function. The velocity distribution is obtained. The results show that the velocity of molten slag varies with different horizontal sections. There are six eddies in the surface layer of molten slag. A large circle is formed in the sections below the electrodes, while the longitudinal section includes two large circles around the electrode. The influences of the features of the velocity field on the operation in the electric cleaning furnace are discussed in detail.