In this work, novel fluorescent carbon dots were prepared via the microwave method utilizing cortex magnoliae officinalis as a carbon source. The size, morphology, and elemental composition of the fluorescent carbon dots were characterized using transmission electron microscopy and X-ray photoelectron spectroscopy. Optical properties of the carbon dots were also characterized based on fluorescence and absorption spectra. Considering the fluorescent quenching of the carbon dots, a new method was developed for the detection of 2, 4, 6-trinitrophenol using the carbon dots as a fluorescent probe. Experimental results reveal that the average diameter of the fluorescent carbon dots is 5 nm, and the main components are carbon and oxygen. Further, the maximum absorption wavelength is 280 nm, and the maximum excitation wavelength is 320 nm; notably, a quantum yield of 0.14 is achieved. Under optimal experimental conditions, the logarithm of the ratio of the fluorescent intensities without and with samples and the concentration of 2, 4, 6-trinitrophenol exhibits a good linear relationship, with a linear range of 0.8-80 μmol/L. Further, the limit of detection is 160 nmol/L. Those results are expected to facilitate the rapid, sensitive, and efficient detection of 2, 4, 6-trinitrophenol in authentic samples.