To investigate the impact of the coupled thermal radiation and noise effects of mobile emergency flares on safe distances and personnel protection strategies, this study adopted a combined method of engineering simulation and theoretical analysis. The thermal radiation and noise impact ranges of a flare of a given specification under different operating conditions were explored, and a quantitative method for determining the minimum on-site safe distance based on work duration, along with a classified personnel protection strategy, was proposed. The results show that, in the absence of protective measures, the noise-determined safe distance of the flare is significantly greater than the thermal radiation-determined safe distance. The minimum safe distance can be defined according to work duration: for long-term operations, the impact distance corresponding to the 85 dB(A) noise limit is defined as the minimum safe distance; for medium-term operations, the impact distance corresponding to the equivalent noise exposure limit is adopted as the minimum safe distance; and for short-term operations, the safe distance corresponding to a downwind thermal radiation intensity of 1.58 kW/m² is taken as the minimum safe distance. In non-safe zones, it is necessary to first identify the thermal radiation intensity and noise sound pressure level at the location, and then determine the protection priorities and strategies based on the duration of stay. Thus, delimiting flare safe distances based on the coupled thermal-noise impact ranges and work duration, and implementing zoned and classified protection measures, can effectively reduce the risk of injury to on-site personnel.