The design and exploitation of highly fire-safe aerogel with ultrasensitive fire-warning response and highly efficient thermal management capabilities are urgently needed to protect firefighters from burn injuries during fire operations and rescue. Herein, an ultralight temperature-triggered fire-warning aerogel composited of polyethylene glycol (PEG)@modified wood powder (MW)/amino-functionalized carbon nanotube (A-CNT)/calcium alginate (CA) (abbreviated as [email protected]) was fabricated. Benefiting the rapid decrease in electrical resistance of A-CNT at high temperatures, [email protected] achieved an ultrafast fire warning response time of ∼2.03 s when exposed to fire. Meanwhile, PEG was encapsulated into MW and acted as microtubule phase-change material ([email protected]) in aerogel to effectively delay the heat penetration into [email protected] The stiff MW served as the backbone endowed the fire-warning aerogel a “stiff-soft” structure that increased the mechanical resilience. [email protected] achieve flyweight density (0.038 g/cm3), low thermal conductivity (0.06233 ± 0.0012 W/m⋅K), and outstanding self-extinguishment (<1.02 s). This work provides an environmental friendliness approach to design an ultralight early fire-warning aerogel in firefighting clothing for enhancing the fire safety of firefighters.