The invention provides a photonic crystal nano-composite gel membrane with temperature/humidity dual responses. 2D colloidal photonic crystals are prepared with soap-free emulsion polymerization and needle tip flow methods, a nano-composite hydrogel pre-polymerization solution is prepared through introduction of inorganic nanoparticles as a physical crosslinking agent, finally, the 2D colloidal photonic crystals and the nano-composite hydrogel pre-polymerization solution are compounded, and the photonic crystal nano-composite gel membrane with the temperature/humidity dual responses is prepared; the photonic crystal gel membrane serving as a sensor realizes effects of fast response, high toughness and excellent optical signal resolution and achieves the purpose of rapidly detecting outsidetemperature/humidity change through color change. Preparation of the gel membrane comprises steps as follows: (1), synthesis of mono-disperse latex particles; (2), preparation of the 2D colloidal photonic crystals with the needle tip method; (3), preparation of the nano-composite hydrogel pre-polymerization solution; (4), preparation of the responsive photonic crystal nano-composite gel membrane.The preparation method is simple and convenient to operate, and the photonic crystal nano-composite gel membrane is high in color change visibility, optical signal resolution and response rate and can be applied to fast detection of temperature/humidity, metal ions, toxicants, biochemical reagents, environmental pollutants and the like.