At present, for in lack of guiding system in the public building in Taiwan, it still is strict challenge for people with visual impairments leaving home and participating social activities. It did not mean the assistance of mobility for people with visual impairments by the other people instead of the improvement of environmental design would be the replace improvement planning in the existing building. Through the analysis of designing criteria of guiding system from USA, European countries and Japan, we found that tactile sign (braille sign) was recognized as low cost, small influence and easily invest would be the proper system for the improvement of existing building. Three selected buildings were physically improved by intervention and processed two experiments, including origin environment and improved environment, by forty people with visual impairments to testify the effectiveness of guiding system. Comparison of origin environment with improved environment and the influence of complex degree of space organization on the effectiveness of guiding system were processed. The finding of this research showed that constructing guiding system by tactile sign (braille sign) greatly assisted blind people and people with low vision. People with low vision spent less time to complete whole route, but blind people spent more time, especially, more complex environment and larger scale environment would need more time to complete route. It had less influence of complex degree of space organization both on blind people and on people with low vision in terms of accurate ratio of wayfinding after constructing guiding system by tactile sign. Obviously, people with low vision were not influenced by complex degree of space organization, nevertheless, blind people decreased accurate ratio of wayfinding and spent more time of wayfinding when space organization became more complex and larger scale environment.