Injection device of trace gas

The utility model relates to an injection device of trace gas comprising a low-vacuum section, a high-vacuum chamber and an ultrahigh vacuum chamber, wherein a gas storing steel cylinder of the low-vacuum section is connected with a magnetic valve, a thermocouple gauge and a fine tuning valve in series through a copper flexible pipe, turbine molecular pump sets are respectively matched on the high-vacuum chamber and the ultrahigh vacuum chamber, which is separated through a seal plate whose middle is provided with flow-limiting eyelets, the seal plate is fixed on a flange, a nozzle is connected at the outlet of the fine tuning valve, the nozzle is communicated with the high-vacuum chamber, the ultrahigh vacuum chamber is communicated with a corrugated pipe, and is connected with the seal plate with the flow-limiting eyelets on the right end of an air-operated valve, the seal plate is fixed on the flange, the left end of the air-operated valve is directly connected with a testing device main body through the f