The online monitoring device for radioactive aerosol concentration is primarily employed to verify the sealing performance of process equipment in nuclear facilities and trigger alarms in the event of highactivity radioactive aerosol concentrations. Currently， such online monitoring devices for radioactive aerosol concentration in nuclear facilities typically exhibit prolonged response times， leading to a lag in monitoring data. In the case of abnormal operating conditions， this may result in elevated radiation doses for personnel. To reduce the response time of online radioactive aerosol concentration monitoring， this study quantitatively analyzes the relationship between monitoring response time and factors including the Minimum Detectable Concentration（MDC）（C _C） of radioactive aerosols， the detection efficiency（η _t） of the monitoring device， and the sampling flow rate（L） through theoretical derivation and data calculation. The results indicate that these three parameters—the MDC of radioactive aerosols， device detection efficiency， and sampling flow rate—are the primary factors influencing response time. Based on these findings， this paper formulates specific measures to shorten response time by optimizing key parameters and provides reference parameter values and equipment selection recommendations. For instance， the MDC can be optimized to 0.05 Bq/m³. Finally， taking a material leakage incident as a case study， the impact of response time optimization on personnel radiation doses is evaluated， and the results confirm that response time optimization can effectively reduce personnel radiation doses by 12.5% to 78.8%.