Considering factors (indicators) such as the air exchange rate, ozone reaction time with air and ozone off-gas destruction technique, the simulation of the Computational Fluid Dynamics (CFD) indicates that the ventilation (flow) of the ozone disinfecting system in a ward should be 300 LPM and the system has better effect being placed on the right side of the sickbed. In this study, the height of the ozone disinfecting system shows no significant effect on the air exchange rate. Besides, if the disposition of the ozone gas is in the ward, the CFD can also simulate the density and distribution of the ozone in the ward. The result can be compared with the maximum NAAQS standard, which is 120 ppb (v/v). Based on the simulation of the flow field, the CFD software can analyze and evaluate the effect of the gases ozone system in a negative-pressure ward. In this study, if the ozone concentration at the outlet of the ozone generator is set at 100 ppm and the flow is set at 300 LPM, then the range of the ozone concentration distributed in the ward should be around 0.045∼5 ppm. According to the related studies by other researchers, the efficacy of the disinfection can reach up to 99%.