Under the background of urban renewal protection and old city transformation, problems such as clutter, distortion, and disorder appear in the historical style area. These problems have greatly impacted and damaged the cultural heritage and historical research of the style area. To carry out the urban renewal movement more reasonably, this article selects the historical features of the Old Town of Shanghai for empirical research, uses the colour patch concept and fragmentation index for a quantitative analysis, and divides the study area fragmentation level. The study found that the number and types of colour patches in the Old Town are many, and the yellow system is highly fragmented in the Old Town, which means that the human environment in the colour style area is lost. The main reasons are the rise of modernist architecture and new materials. Three aspects are involved in the widespread use of policy and out-of-control management of the policy; therefore, attention should be paid to the updating of future historical style areas: protecting the authenticity of colours, maintaining colour integrity, and continually retaining colour memories in cities.