An eco-friendly fluorescence polymer nanoparticle based on carbon quantum dots and poly(methyl methacrylate) nanoparticles is successfully fabricated to detect sulfadiazine. By making use of the abundant functional group of carbon quantum dots and poly(methyl methacrylate) nanoparticles, without any extra modification, the synthetic process of the fluorescence nanoparticles is reduced and the unnecessary chemical molecules are avoided being brought into the reaction system. The investigation of the fluorescence property of carbon quantum dots shows that the prepared carbon quantum dots are the excitation independent. In addition, the morphology of the synthesized fluorescence polymer nanoparticle is tested by the scanning electron microscope and shows that the fluorescence sensor possesses a good spherical core-shell structure. Moreover, under the optimized condition, the prepared fluorescence polymer nanoparticle possesses a good selectivity in the detection of sulfadiazine under a mixture solution. Moreover, the limit of detection is 4 μmol.l-1 within the detective range from 10 μmol.l-1 to 60 μmol.l-1. Meanwhile, the fluorescence quenching mechanism is considered with the photoinduced electron transfer mechanism. Finally, the practical research on the detection of sulfadiazine in tap water shows that the recovery range and relative standard deviation are 97.5% - 105.1% and 2.1%-4.5%, respectively.