Abstract: This study conducted numerical simulations and parameter studies on the reflux temperature field and the temperature rise after the jet blast deflector (JBD) plate caused by the impact of the wake jet of carrier based aircraft during the takeoff process. Firstly, an aircraft model with twin high-thrust engines was designed, and the accuracy of the Computational Fluid Dynamics simulation using the k-ε turbulence model in calculating the jet and reflux velocity fields was verified through comparison with the wind tunnel test data. Then, by controlling variables, influences of the nozzle axis angle, nozzle spacing, and nozzle expansion angle on the temperature distortion intensity at the exit of the inlet and the total temperature field behind the JBD were studied. It is found that, increasing the upward tilting angle of the nozzle axis or increasing the nozzle spacing can effectively reduce the intake of high temperature reflux and the extreme values of the temperature field behind the JBD; when the nozzle spacing increases to three times the nozzle throat diameter, the temperature rise at the exit of the inlet is almost zero. Finally, to improve the JBD design, without adding additional equipment on the ship surface, the effect of transverse slotting on the JBD’s flow guiding ability was studied, which suggests that transverse slotting on the JBD surface can enhance the circumferential injection ability of the wake jet and effectively reduce the intensity of the reflux temperature field.