Nowadays the web sites are designed in size of 1024*768 pixels and those have a tendency to change by little effect that monitors become wider and wider. As the existing method of broadcasting image output changes from analog method to HD method, also the computer display ratio that is concerned about multimedia environment importantly is being turned out with 16:9 wide. This research suggests the web design modular which is applied a golden proportion in ratio of the 16:9 based on the proporrion analyzed case study of web sites for art museum. In the analysis of the case study, following activities are executed which are following the standard of ‘www.rankey.com’ which provides the rank of museum websites, analyzing the structure of those ratio and layout, dividing the visual facts and info-structural facts which are accomplished the grid and collecting the responder`s objective opinions by the proportion preference questions. Through the analysis of the case study, I invented and applied a modular which was able to contribute to design layouts effectively based on the principle of the golden proportion. The invention of modular was decided by the proportion of 16:9 and the vertical and horizon proportion inside was divided by the proportion of 0.618:1, which was produced by dividing itself inside of the section. This study can contribute to design web sites which have a visually stable proportion and to raise the efficiency of work by suggesting the minimum guide in order to design web sites. Furthermore, in the future, this can be applied the variety of media which are designed by the wide displat as a standard.