The hydrodynamic model is established in the sea area of the Zhoushan Tidal Stream Energy Demonstration Project. The proposed model is based on the open source code OpenTidalFarm and verified by the observed data. In this model, the effect of tidal stream turbine is approximated by a locally-increased bottom friction and the turbines layout is optimized by the iterative algorithm and adjoint method. The result shows that the tidal current energy extracted by the optimized array is 15. 2% higher than that of initial regular array, which can be a reference for the development and utilization of tidal current energy in the Demonstration Project of Zhoushan Tidal Stream Energy.