As a common air pollutant, nitrogen dioxide (NO₂) gas does serious harm to the natural environment and human health. Therefore, it is imperative to develop efficient detection methods for detecting such toxic and harmful gases. Developing a new type of composite film gas sensor to achieve high selectivity and high sensitivity detection of nitrogen dioxide at room temperature has become a research hotspot. Here, we prepared zeolitic imidazolate framework 8 /reduced graphene oxide (ZIF8/rGO) composite with porosity and large specific surface area through chemical precipitation and ultrasonic method. Based on this materials, an NO₂ sensor was constructed and then evaluated at room-temperature. Its possible mechanism of sensing NO₂ was explored. The results showed that ZIF8/rGO sensor presented a response of 34.77% toward 50×10^-6 NO₂, which was 3.2-fold of pure rGO senor. Meanwhile it exhibited excellent repeatability after 4 reversible cycles with the relative standard deviation (RSD) only 3.9% and remarkable long-term stability in four-week test with the RSD of 2.5%, accompanied outstanding selectivity toward NO₂ and a low limit of detection of 3.8×10^-8. These hypersensitive properties at room temperature were attributed to its porous structure and large specific surface and high performance of rGO. This work offers a new idea for efficiently detecting poisonous NO₂ based on ZIF8/rGO.