This experiment was carried out to figure out the CO2 biomass and the growth response of Chinese cabbage and radish grown under the condition of high temperature and high CO2 concentration to provide the information for the coming climatic change. Chinese cabbage and radish were cultivated in spring and autumn seasons under 4 treatments, 'ambient temp.+ambient CO2 conc.', 'ambient temp.+elevated CO2 conc.', 'elevated temp.+ ambient CO2 conc.', and 'elevated temp. +elevated CO2 conc.'. The 'elevated temp,' plot was maintained at 5 higher than 'ambient temp. (outside temperature)'and the 'elevated CO2 cone.' plot was done in 650 ppm CO2. The growth of spring-sown Chinese cabbage was worse than autumn-sown one, and was affected more by high temperature than high CO2. concentration. The CO2 biomass of Chinese cabbage was lower as 25.1-39.1 g/plant in spring-sown one than 54.8-63.4 g/plant of autumn-sown one. Daily CO22 fixation ability was not significantly different between spring- and autumn-sown Chinese cabbage as 1.9-2.9, 2.7-3.1 kg/10a/day, respectively. The CO2 biomass of radish were 87.4-104.6 /plant in spring-sown one and 51.3~76.4 g/plant in autumn-sown one. Daily CO2 fixation ability of radish were 6.2-10.1 kg/10a/day in spring-sown one and 4.6-6.9 kg/10a/day in autumn-sown one.