Carbon quantum dots, as an emerging zero-dimensional carbon-based nanomaterial, have shown great potential applications in fields such as biomedicine, sensing detection, and LED lighting due to their excellent photoelectric properties, good biocompatibility, and ease of functionalization. Traditional synthesis methods like hydrothermal and microwave approaches often face challenges such as harsh reaction conditions, long reaction times, high energy consumption, and difficulties in controlling the optical properties of the products. The plasma electrochemistry method, which utilizes reactions between carbon source molecules and high-density electrons, ions, photons, and reactive radicals generated during the interaction of plasma with liquid, can efficiently drive the rapid synthesis and modification of carbon quantum dots. This method possesses the advantage of tunable multiple reaction parameters under mild conditions, providing a novel research method for synthesizing and modifying carbon quantum dots. This article first elucidates the growth mechanism of carbon quantum dots synthesized via plasma electrochemical methods and highlights the unique advantages of this approach in controlling product properties by regulating multidimensional parameters. Then, it reviews research progress of the regulation of the fluorescence quantum yield and wavelength of carbon quantum dots based on the adjustment of plasma reaction parameters. Finally, this article presents the application progress and prospects of plasma-prepared and plasma-modified carbon quantum dots in biomedicine, optoelectronic devices, pH sensing, and other fields.