The invention relates to an automatic monitoring device for outdoor air, a carbon dioxide concentration and environmental parameters, which comprises a soil and air gas collection unit, a gas circulation and control unit, a gas concentration online detection unit, an environmental parameter collection unit, a central control unit, a wireless data transmission unit and a solar power supply unit, wherein the soil and air gas collection unit transmits the collected data to the gas concentration online detection unit and the central control unit through the gas circulation and control unit respectively; the gas concentration online detection unit also transmits the detection result to the central control unit; the environmental parameter collection unit also transmits the collected data to thecentral control unit; the central control unit transmits the data to a 4G/3G/GPRS network through the wireless data transmission unit to realize data communication; and the solar power supply unit supplies power for the whole automatic monitoring device. A basis for fast and accurate judgment on the concentration of deep-source carbon dioxide and the influences of the surrounding environment on the diffusion of carbon dioxide can be provided.