In　this　study,　the　sulfonic　group　was　introduced　to　prepare　high-performance　Eucommia　ulmoides　lignin-based　biochar,　which　was　used　to　remove　tetracycline　hydrochloride.　The　BET　area　(2008　m(2)　g(-1))　of　sulfonated　biochar　was　twice　that　of　unmodified　biochar.　Through　XRD　and　Raman　analysis,　the　synergetic　pyrolysis　mechanism　of　the　sulfonic　group　in　the　formation　of　the　porous　structure　was　discussed.　Sulfonated　biochar　had　excellent　adsorption　performance　for　tetracycline　hydrochloride　(Q(m):　1163　mg　g(-1)),　while　the　adsorption　performance　of　unmodified　biochar　was　about　only　one-fourth　(Q(m):　277.7　mg　g(-1))　of　that.　The　adsorption　of　tetracycline　hydrochloride　by　the　sulfonated　biochar　was　spontaneously　endothermic　and　conformed　to　the　Langmuir　isotherm　model.　The　adsorption　process　was　confirmed　by　pseudo-second-order　kinetic　model.　Moreover,　the　sulfonic　group　on　the　sulfonated　biochar　significantly　promoted　the　formation　of　the　hydrogen　bond　and　greatly　improved　the　adsorption　performance.