The experiments were conducted to examine the injuries of SO_2, NH_3, and SO_2 and NH_3 mixed gas to the germination and the growth of plants. Six kinds of plants were used as the material. These plant seeds were treated with the gases for five days. Rate of the germination and the growth in height of varying plants were different according to the components of the gases. The critical concentration of the gases for both the germination and the growth were in 5ppm of SO_2, 50ppm of NH_3, and 50ppm SO_2 and 50ppm NH_3 mixed gases. When a low concentration of SO_2 was treated together with NH_3, especially it was reduced to 60 percent of the damage in the germination and the growth. In the treatment with SO_2, the germination of the seeds which soaked in water for 24 hours reduced the injuries more 40 percent than those which for one hour. It was observed that the seeds with thick coats or with originally intact coats were suffered but little damaged by the gases, and the external symptoms of an injury were shown, at first, in water pore, and then, in guard cell on the leaves.