Flame retardant cotton fabric has attracted extensive attention and research with the increase of public safe awareness. However, it still remained a great challenge to balance the performances of high flame retardancy, durability, mechanical strength, as well as formaldehyde-free, comfort, green and feasible process. Herein, efficient, durable and breathable flame retardant cotton fabrics were fabricated through a one-pot approach based on a synergetic system combining phytic acid (PA) with polyethyleneimine (PEI) and 3-Glycidyloxypropyltrimethoxysilane (GPTMS). The modified cotton fabrics displayed high-efficiency fire resistance, self-extinguishing and excellent washing resistance due to the formation of surface hybrid network architectures from multiple covalent bonds (SiOC, CN, POC) and electrostatic assembly. The limiting oxygen index (LOI) could retain at 27.1% after 50 laundering cycles (LCs). Moreover, the peak of heat release rate (PHRR), total heat release (THR) and total smoke release (TSP) declined by 85.89%, 52.72% and 47.22% compared with neat fabric, indicating boosted flame retardance and excellent smoke suppression ability. In addition, the proposed surface finishing process substantially retained the mechanical properties and moisture permeability, providing a simple and feasible approach for high-efficiency, durable and breathable flame retardant cotton fabric.