Graphene has unique properties such as high electron mobility, large specific surface area, high mechanical strength, excellent chemical and thermal stability, and high electrical conductivity at room temperature. It is one of the most popular two-dimensional materials today. Compared with traditional inorganic oxide materials, graphene gas sensors have the advantages of low operating temperature, low energy consumption, and high recovery. The research progresses of two graphene gas sensors were summarized in this paper. Firstly, according to the different gas selectivity, graphene gas sensors were divided into CO and CO2 gas sensors. Then, the sensitivity, gas response sensitivity and response time were analyzed and compared, respectively, which had certain guiding significance for the practical application and promotion of this type of sensor.