In order to work out statistics of environmental functions of indoor landscape plants in architectures, this study aims to conduct a simulation of how much control plants have over overheating phenomena in atria in summer, involve themselves in air current speed and maintain indoor comfort index, with a numerical analysis model. Thus, nine kinds of representative plants which are usually used for indoor environments were selected, and purified with two irrigations a day for two weeks. And then, their transpiration and photosynthesis amounts were measured three times with a photosynthesis analysis system LICO-6400 at 38℃, which is the highest temperature in the atrium in summer. The data were organized, and another three plants with similar transpiration and photosynthesis amounts were selected. The leaf area which accounts for 10% green zone rate inside the atrium was calculated, and the leaf surplus was removed. And then, the plants were left inside the atrium, and transpiration amount and temperature change were automatically measured for three hours. The maximum temperature change by transpiration of plants was found to be 2.21~2.92℃, which means 0.21~0.23℃ per every 100cm² of leaf area.It is hard to see air current change in atria as convection by plants as the change is at undetectible level with a distribution of 0.08~0.005m/s. However, if air current change is made with fans even in natural air current situations, air current becomes active inside atria as rather cold air moves upward. Therefore, if 0.5 m/s of air current change is made with upward and downward fans in atrium models, the air current speed in the entire atrium converges to the level which gives the most comfort to human.