A frequency stabilized single longitudinal mode (SLM) laser is widely used in coherent detection, high-accuracy laser ranging, high-resolution spectrum, laser radar, etc. TEA CO2 laser seed injection technique is researched theoretically and experimentally. The SLM TEA CO2 laser output is obtained through frequency stabilized seed laser injection design. The preliminary experimental research is performed to obtain SLM laser output with 100 mJ single pulse energy and 10.59 μm (10P20) output laser wavelength, which is the same as the injection seed laser wavelength, and the experimental results are analyzed. In this method, the wavelength, far field beam divergence angle, frequency stability and M2 factor of the output laser are the same as those of the seed laser, so if a high beam quality seed laser source is used, a high-power output of the laser with high frequency stability and high beam quality will be got, and it is significant to scientific and national defense use.