Extreme climatic alteration has provoked an increase in global forest grassland fires. The establishment of emergency firebreaks is essential for managing the occurrence of sudden forest grassland fires. However, conventional methods entail substantial labor, exorbitant costs, and limited emergency response, impeding the prompt and efficient containment of fire outbreaks. Therefore, constructing rapid implementation of emergency firebreaks is pivotal for the precise prevention and control of forest grassland fires. Herein, a multi-element synergistic surface-modified bio-based flame retardant with catalytic carbonization was fabricated, which can catalyze and bolster the dehydration of phosphate compounds into char during combustion. The fire resistance of vegetation is significantly enhanced by synergizing with ammonium polyphosphate (APP), resulting in peak heat release rate, total heat release, and total smoke production respectively exhibiting 35.5 %, 22.9 %, and 47.5 % reduction. The catalytic carbonization behavior and mechanism of it were further investigated in this work. Furthermore, the synergistic effect of the fire retardant was confirmed through fire spread experiments, demonstrating the capability to suppress flame propagation by restraining the decomposition of vegetation and debilitating thermal radiation. Overall, this study aims at providing a cost-effective, rapid, and efficient method for establishing emergency firebreaks in challenging terrains.