This work reports the synthesis of a magnetic weak anionic spherical adsorbent with large size and starlike structure by magnetic induced self-assembly of organic latexes followed by modification with diethylaminoethyl hydrochloride (DEAE-HCl). The prepared adsorbent features unique starlike long chains stacked by anisotropic latexes (1 mu m), large particle size (250 mu m), and magnetic response. According to N-2 adsorption-desorption analysis, the starlike adsorbent possesses both specific surface area of 55.2 m(2) g(-1) and total mesopore volume of about 2.7 cm(3) g(-1). After being modified with DEAE, the weak anionic adsorbent is evaluated for its adsorption performance. The analysis proves that the adsorbent approaches not only high static adsorption capacity of 113.05 mg mL(-1) for BSA adsorption but also fast adsorption rate for approaching the adsorption equilibrium within less than 40 min. Additionally, the large particle size and magnetic response of the adsorbent facilitate the easy recovery of adsorbent from aqueous solution by simple filtration and/or external magnetic force. Hence, the prepared magnetic starlike spherical adsorbent is expected to have potential application in high-performance and large-scale purification of proteins.