Slab CO2 laser with diffusion-cooling and RF pumping has the advantages of high efficiency, small size and good beam quality, and this kind of laser has been applied in laser precision annealing, industrial processing and some other fields. High-power RF pumped, diffusion-cooled slab CO2 laser with more than kilowatts power output plays an important role in the precision processing and micro-electronic equipment because of its high beam quality and high stability. In this paper, the progress of CO2 laser technology, focusing on research trends of the RF excited slab structure with high power output, was analyzed in detail, and the development stages and applications of this technology was summarized. Finally, the research tendency of slab CO2 laser was prospected.