Based on the mathematical model of the wind supercharged solar chimney power plant combined with seawater desalination (WSSCPPCSD), the velocity field characteristics of basic WSSCPPCSD were analyzed through three-dimensional numerical simulation. To investigate the influence of different structural parameters of system performance, systems with turbines of different blade numbers, installation angles and relative radial clearances, with guide cone or guide vane were also simulated. Unsteady numerical simulations of H-type wind pressure ventilator with different wind wheel blade installation angles were conducted, as well as another helix-type wind pressure ventilator. The results show that the increase of turbine blade number could lead to a reduced freshwater productivity, and the rotational speed corresponding to maximum turbine shaft power shifts in the direction of lower speed. Besides, with the increase of blade installation angle, both the freshwater productivity and the turbine shaft power increase first and then decrease. As the radial clearance of turbine blades increases, the system freshwater productivity increases and the noise decreases, and the turbine shaft power has a maximum value when the relative radial clearance is 2%. The addition of guide cone and guide vane can effectively improve the flow field. As for the wind pressure ventilator, system freshwater productivity and shaft power both increases first and then drops with the increase of wind wheel blade installation angle. In addition, the helix-type wind wheel can improve the self-starting performance of the wind pressure ventilator and decrease the fluctuation of blade torque at the same time, so as to improve the stability.