A three-dimensional mathematical model has been developed to study turbulent fluid flow, heat transfer and free surface profile in the initial stage of the twin-roll casting strip pool by a commercial software ProCAST. The coupled set of governing equations for mass, momentum and energy balance was solved with the finite element method. The free surface profile of the pool was treated with the Volume of Fluids (VOF) approach. A straight nozzle of metal delivery system has been chosen in the Twin-roll strip casting process. The filling sequences, flow patterns and corresponding temperature profiles in the metal pool of a vertical twin-roll strip casting process were simulated in this study. The calculated results provided a valuable basis for the optimization of process parameters and metal delivery system during the initial pouring stage of twin-roll strip casting.