To deeply explore the hot topics and evolution trends of postgraduate dissertation topic selection in urban and rural planning， based on the dissertation database of CNKI， this paper uses CiteSpace visual analysis tool to conduct a multi-dimensional analysis of relevant dissertations， including keyword co-occurrence， clustering， time sequence and burst detection. The study aims to reveal the spatiotemporal distribution characteristics and dynamic evolution rules of dissertation topics， so as to provide a theoretical basis for disciplinary reform and development. It finds that influenced by disciplinary characteristics， dissertation topics have always adhered to the core of physical space and maintained a distinct disciplinary nature. Meanwhile， with the changes of the times， driven by national policy orientation， social demand changes and knowledge system innovation， the perspective of topics presents a diversified divergence trend， the proportion of thematic research has increased significantly， and the interdisciplinary integration trend with space+ as the core has become increasingly prominent.