Carbon coated Fe3O4 nanoparticles (Fe3O4@C NPs) were synthesized by using citrus pectin as the carbon source. The as-prepared nanoparticles were spherical with the smallest, uniformly size of 7nm among all reported and large specific surface area. Surprisingly, the Fe3O4@C NPs further demonstrated dramatic ability to remove methylene blue for a maximum adsorption capacity of 141.3mgg−1 and superior recyclability up to 20cycles. Further experimental results revealed that the adsorption kinetic and isotherm fitted well with the pseudo-second-order kinetic and Freundlich isotherm model, respectively. The nanoparticles were further used efficiently to remove methylene blue from spiked environmental water sample. Thus, the synthesized Fe3O4@C NPs hold great potential for dyes removal in the wastewater treatment while opening a new path for efficient utilization of citrus pectin.