For forming adsorbents, the stability of cyclic adsorption is as important as the adsorption properties. In this work, A shell-type self-assembled mineralized adsorbent based on Ca-alginate was synthesized for Hg(II) adsorption. The synthesis process consists of gelation of Ca-based spherical polymer template (CAB) and rate-controlled self-assembly mineralization in bicarbonate solution. A shell-type porous crystal layer is proved to be formed on the surface of the organic polymer template by rate-controlled self-assembly mineralization. The single-factor experiment demonstrates that 1% (MCAB-1) is the optimal concentration of bicarbonate. A maximum adsorption capacity, 48 ± 4 mg/g of MCAB-1 was observed at a pH = 5 in batch test, which was 2.67 times that of the unmodified one, CAB, 18 ± 1 mg/g. Long duration (10 h) adsorption tests showed that MCAB-1 exhibited remarkable performance stability and anti-wear ability (43.2 % removal efficiency and 74.3 % mass retention, compared to 2.7 % and 38.6 % of CAB at pH = 3, respectively). The results show that the adsorption and wear resistance of the modified materials are improved obviously.