The purpose of this study is to understand the physical responses of males and females according to the changes of environmental colors in R(red) and G(green). This study is also focused on collecting and arranging the environmental color data being possible to reduce stresses. The experimental study was carried out in a lighting-controlled room sized in 3.5m X 2.7m X 2.8m(H), and a heart rate variability experiment device called ‘‘UbioMacpa’ was used. Total 6 colors such as ‘pale’, ‘bright’ and ‘vivid’ tones of R and G groups were selected from NCS color system as stimuli, and 20 subjects(10 male and 10 female) were participated in the experiment, measuring their heartbeats as human body physiology responses. As results, the difference of stress index between and males and females was not outstanding, despite the females showed a slightly higher stress index. But there was a significant opposite result between the male and female, in the cases of HF, LF/HF in ‘bright tone of G’, and LF in ‘bright tone of R’. Finally, obvious differences between male and female were shown in the case of ‘bright tone of G’, and it means that physiological responses according to color environment differ between genders.