Dalian, a typical modern colonial city, originated in the late 19th century and was planned and built by Russian architects. Academics have traditionally focused on the unique qualities of the spatial form from the early stages of urban development, but due to a lack of urban history archives, the formation of the spatial form and the planning ideology of this time have not been examined. For this study, we visited the Russian State Historical Archives to search for relevant materials to restore the process of forming Dalian’s spatial form. Based on this, the heritage value and attributes of Dalian’s modern urban spatial form are discussed. The results show that, although Dalian was always under the control of Russian political power at the early stage of its urban construction, the urban planning ideas were integrated with modern Western urban planning ideas. Secondly, under the influence of modern Western urban planning ideas, including “classicalism” and the “garden city”, the modern Dalian urban space gradually formed a unique form and appearance, bearing the brand of the times and urban memory in a special context. Moreover, this study finds that the evolution of urban space is not simply a cumulative development of itself but the result of the influence of external ideas implanted with unique heritage values and attributes.