In recent years, the water quality of micro-polluted landscape water shows the deterioration trend of ammonia nitrogen and chemical oxygen demand (COD) exceeding the standard. The use of adsorption materials is one of the effective ways to solve this situation, but such materials often do not have long-term stable in-situ treatment performance. To solve this problem, the alkalized bentonite-calcium alginate immobilized particles were prepared by using calcium alginate with good biocompatibility as a fixative. And the removal effect of NH3-N and COD in simulated micro-polluted water was investigated by using immobilized particles as microbial carriers. A series of alkalized bentonite-calcium alginate immobilized particles were synthesized by sol-gel method using calcium alginate to fix alkaline bentonite, which was treated with different concentrations of NaOH solution. The prepared alkaline bentonite and immobilized particles were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Zeta test and BET specific surface area test. Meanwhile, the treatment performance of immobilized particles on micro-polluted wastewater as microbial carriers was analyzed. The results showed that the bentonite treated with 0.5 mol/L NaOH solution increased surface lamellar structure, and had the lowest Zeta potential of -27.4 mV, which meant that the surface electronegativity was enhanced. 0.5B-CA immobilized particles had the maximum BET specific surface area of 12.1 m2/g, which was 28% higher than that of 0B-CA immobilized particles, providing more sites for microbial attachment. 0.5B-CA immobilized particles as microbial carriers had the best removal effect on NH3-N and COD. In the 10 cycles of treatment, the concentration of NH3-N and COD in all treated wastewater were reduced to below 1 and 20 mg/L, respectively, reaching the national surface water environment class III water standard. The combination of adsorption of bentonite as adsorption matrix and microbial removal makes the material as microbial carrier show excellent removal performance and long-term stable removal ability of NH3-N and COD, which provides the possibility for its application in practical scenes.