Carbon dots (CDs) have garnered attention for their potential applications across diverse fields. This is attributed to their characteristics, which include abundant raw material sources, uncomplicated surface modification, cost-effectiveness, excellent fluorescence, low toxicity, and biocompatibility. In this review, we have introduced the top-down and bottom-up synthesis techniques of CDs. Then, we discuss their physical, chemical, and optical features and focus on their diverse applications in environmental analysis, including metal ion sensing, contaminants detection, photocatalysts, and other aspect. We presented conclusions and future perspectives on the challenges of CDs. The review will provide insights into the evolving landscape of CD research and its pivotal role in advancing environmental analytical techniques.