Fe-N-doped biochar is a promising material for advanced-oxidation heterogeneous catalysis, but its adsorption-catalytic performance is significantly affected by biomass feedstock compositions and thermal conversion conditions and is not yet conclusive. In this paper, four lignocellulosic biomasses (rice straw, bamboo, poplar wood, and corn stover) were selected as raw materials to prepare Fe-N-biochar as persulfate activators by hydrothermal-thermolysis composite. Their lignocellulosic fractions and elemental contents were detected, and a variety of thermal conversion conditions were investigated for the rice straw-based Fe-N-biochar with the best activation performance among them. It was found that the holocellulose and lignin contents of the biomass affected the catalytic activity of the prepared catalysts with correlation coefficients of 0.57 and 0.93, respectively. Increasing the pyrolysis temperature from 500 degrees C to 800 degrees C could increase the ratio of Fe2+/Fe3+ and the relative amounts of C=C, graphitized N, and oxidized N in the catalyst by 0.17 %, 7 %, 12 %, and 18 %, respectively. Extending the pyrolysis time from 0.5 to 2 h was able to increase the relative content of C=C, graphitized N, and oxidized N by 0.18 %, 3 %, 9 %, and 4 %, respectively. The most catalytically active rice straw-derived Fe-NRBC was able to remove 91.7 % of sulfamethoxazole (SMX) and 93.07 % of TOC mainly via center dot SO4- and center dot OH in an adsorption-catalytic reaction of 60 min with a k of 0.047 min(-1) and the main active sites are Fe-N, Fe-0, pyridine N, oxidized N and C=O. Finally, degradation intermediates and pathways were also characterized. This paper is expected to provide a basis for the future targeted regulation of Fe-N biochar for water pollution treatment.