The present invention relates to a gas analysis injection apparatus, which comprises a main gas pipeline provided with a first chromatographic column, a first branch gas pipeline connected to the main gas pipeline and a second branch gas pipeline connected to the main gas pipeline, wherein the first branch gas pipeline is provided with a switching valve, a second chromatographic column is arranged on the second branch gas pipeline in a serial manner, and the gas analysis injection apparatus further comprises a sensor apparatus for detecting the components of the gases in the first branch gas pipeline and the second branch gas pipeline. According to the present invention, the connecting positions of the main gas pipeline and the first branch gas pipeline and the main gas pipeline and the second branch gas pipeline are provided with the connecting member to switch the gas path of the chromatographic column so as to reduce the baseline fluctuation produced by the gas chromatogram, ensure the stability of the output baseline and the accuracy of the sensor signal, and increase the effective utilization rate of the chromatographic column.