Abstract: Using "municipal solid waste incineration (MSWI) fly ash" as the keyword, the relevant patents with a global application deadline of December 31, 2023 were retrieved from the Incopat database. Clustering analysis was conducted by leveraging the patent content analysis module on the Incopat platform in tandem with Zotero 7.0.3 software. Visualization analysis was carried out by utilizing the patent value evaluation module of the Incopat platform, along with Origin Pro 2024 and Adobe Illustrator 2022. The results indicate that since the first global patent application for MSWI fly ash in 1964, the number of patent applications for related technologies has shown an overall upward trend. As of December 31, 2023, a total of 3 884 patents on MSWI fly ash were identified, among which 2 960 were Chinese patents. This demonstrates that China is the primary source country of global MSWI fly ash patent technology and a major producer of high-value patent technology. The core components of both domestic and international, as well as high-value, patented technologies for MSWI fly ash are centered around solid waste treatment. Technological applications are predominantly distributed in the fields of energy-incineration and method-process-treatment/preparation. Co-occurrence clustering analysis revealed five distinct clusters within the realm of Chinese MSWI fly ash patent technology, namely resource utilization, leaching toxicity, domestic waste, high-temperature melting, and fly ash. Research efforts primarily focus on aspects such as water washing, fly ash storage, dioxin management, leaching toxicity control, the use of polymer chelating agents, the development of solidifying bodies, pretreatment methods, and gelling materials. Notably, in recent years in China, co-processing and patent technologies about building materials have emerged as novel approaches and crucial research directions.