Carbon　quantum　dots　(CQDs)　are　zero-dimensional　carbon　nanomaterials　known　for　their　significant　fluorescent　properties.　Due　to　its　potential　biocompatibility,　water　solubility,　stable　optoelectronic　characteristics,　ease　of　functionalization,　and　outstanding　stability.　It　is　gradually　receiving　attention　from　researchers　in　multiple　fields.　Based　on　an　in-depth　analysis　of　domestic　and　foreign　databases.　Especially　combining　with　the　analysis　of　relevant　literature　publication　trends　and　disciplinary　distribution　characteristics　on　CNKI,　explore　various　preparation　methods,　especially　hydrothermal　methods　focusing　on　hydrothermal　synthesis.　It　categorizes　common　raw　materials　and　explores　their　applications　in　bioimaging,　fluorescent　materials,　photocatalysis,　and　ion　detection.　This　research　enhances　our　understanding　of　CQD　preparation　methods　and　characteristics,　providing　important　academic　references　and　insights　for　future　research　and　applications.　©　2025　SPIE.