In the digital era, big data technology is profoundly affecting various fields, including rural design and cultural heritage protection. The study first uses the TF-IDF method to count the vocabulary and word frequency in the texts of rural in situ design and cultural heritage protection in Jiangsu. Then the related image symbol elements are clustered separately using the LDA theme model. Finally, combining the SO-PMI method, an affective dictionary was constructed to reveal the public’s affective cognitive attitudes towards the current design of the Jiangsu countryside in locality and cultural heritage protection through the SO-PMI values. The total SO-PMI values for the current rural on-site design and cultural heritage protection in Jiangsu are -85.4 and -58.6, respectively, and the public’s affective attitudes towards them are not optimistic. For this reason, this paper combines the specific analysis results of each image category, and proposes that the local design of Jiangsu countryside should emphasize the cultural characteristics of the local area, the social needs of the group, and the public spirit of the countryside to be remodeled. Cultural heritage can be digitally protected through methods such as information databases, digital archaeology, virtual interactive design, digital museums, and digital publishing.