Noise and nitrogen oxide (NOx) pollution are harmful to human health, and using sustainable materials such as discarded wood to fabricate insulating building materials can address the issues of environmental pollution and energy crisis. Thus, fabricating multifunction materials with discarded wood by advanced technology can bring exciting innovation. In this study, a novel “weather-resistant wood” with superior weathering resistance, sound absorption, thermal insulation, and photocatalytic properties is reported. The weather-resistant wood was prepared using a simple high-temperature alkali treatment method that allowed the introduction of alkali metal-doped and N-vacancy rich C3N4 onto the wood. The prepared weather-resistant wood sample (with a thickness of 10 mm) exhibited a high porosity of 89.6 %, noise-reduction coefficient of 0.28, and thermal conductivity of 0.0586 W m−1 K−1. Moreover, it could remove 45.4 % of ultralow concentrations of NO (∼500 ppb) under visible-light irradiation. The developed weather-resistant wood demonstrates considerable potential for applications in our lives including noise reduction and improvements in air quality.