Abstract: Wheat and rice straw were used as the raw material of biochars. The biochars were pyrolyzed under oxygen-limited conditions at 400 ℃, and their compositions were characterized by thermogravimetric analysis (TG-DTG), elemental analysis, BET-N₂ specific surface area analysis and Fourier Transform Infrared Spectroscopy (FTIR). The sorption characteristics of the biochars with the typical natural estrogen 17β-estradiol (E2) were investigated. The results showed that the biochars had two weightlessness peaks at 40-70 ℃ and 300-350 ℃, respectively, which represented dehydration and cellulose pyrolysis. Elemental compositions of C, H, O and N were 59.45%, 2.81%, 20.17% and 1.20% for wheat, and 51.14%, 2.44%, 17.02% and 1.04% for rice, respectively. Both the rice and wheat biochars were rich in aromatic functional groups and contained inorganic mineral components. The surface areas of the wheat straw and rice straw biochars were 51.36 and 28.63 m²/g. The adsorption kinetics curves were fitted well with the Elovch equation. Adsorption thermodynamics curves were consistent with the Freundlich equation. The parameters values of nonlinearity index (n) were 0.46 and 0.42, while the sorption affinities (K_f) were 2526.15 and 4368.23. The adsorption curves were fitted well with the dual-mode model. Q₀, the adsorption capacity, showed a good positive relationship with the volume of pores whose sizes were less than 20 nm. Partition fractions show great differences according to different raw materials; the influencing factors still need to be further studied.