This paper aims to study the effect of blue color on users of architectural spaces in general, and for people with intellectual disabilities in particular, with the aim of improving their mental skills. By controlling the color of the interior space and studying the effect of color on many cases through their presence in the specified space and their exposure to color. The study included 73 cases with different mental problems. We exposed 33 cases to Blue, while we left another group of 40 cases without exposure to it. Exposing cases to blue took two hours a day for two days a week. Intelligence tests were done for each condition, pretest (at the start of the study), and posttest (six months after the first test). The study showed that the exposure to blue color made an increase in the percentage of intelligence of cases that were exposed to blue color compared to those that were not exposed to it. Since this research aims to study the possibility of increasing the intelligence of cases with different mental problems, the aim was to study the effect of blue to increase their Intelligence quotient (IQ) compared to those who are not exposed to it. The intelligence tests that applied to different cases of people with intellectual disabilities compared to those that were not exposed to blue expected to show if there is an impact.