Since most construction workers comprehend information on work through sight, the importance of safety signs are increasing by the day. In Korea, due to the sharp economic progress and the higher standard of the workforce, since the end of 1980, each year the number of foreign workers entering the country who working simple technical jobs have increased this condition. This study researched safety signs, which are the final accident prevention measures at the workplace. Based on the study, comprehension of the standard safety signs of the Occupational Safety and Health Act (OSHA) was lacking at a level of 2.5. Also, the perception level of the Industry Public Safety Law (38%) was very low. And, it was found that sex and experience or non-experience in safety training was not an issue in the level of understanding. However, when satisfying the standards of the Occupational Safety and Health Act and changing the safety signs, the level of understanding went up to 3.49 and the perception level was increased significantly to 70%. Thus, it is concluded that, since the foreign workers are mainly from non-English speaking countries and because the workers of Korea are not familiar with English, in order to provide proper safety information, there must first of all be simplistic and concise pictograms. This will provide needed information and must be coupled with simple English words that can give additional information to the worker and be effective in helping him understand and perceive the safety sign. Also, it has been determined that the existing forms of safety signs and their effectiveness in industry accident prevention must be reassessed.