This study aims to explore and discuss the architecture of Saudi Arabia. Taking Jeddah as a case study, by defining the advantages and characteristics of the local architecture and the texture of the old city, it pays full attention to the physical transformations that have been adopted. It occupies a place in the urban planning and architectural form of Jeddah. However, the main objective of this study is to discuss the effect of modernization and westernization on the physical appearance of the city, comparing it with the local old urban fabric and buildings, and finally criticizing the impact of the modern movement in Jeddah in terms of the environmental, cultural and Islamic aspects. All in all, this study considered the most traditional of Jeddah as the main case study and outlined the effect of modernism and westernization in Jeddah, as well as criticized the modern architecture and urban planning in Jeddah.