A microspheres (CA/BC7) was prepared using calcium alginate (CA) encapsulated biochar (BC7) as the green adsorbent for Cu(II) removal from aqueous solution. The effects of the initial Cu(II) concentration, initial pH value of Cu(II) solution and equilibrium contact time were investigated. The isothermal thermodynamic datas of the BC7 and CA/BC7 conformed to the Langmuir model. The maximum adsorption capacity of the BC7 and CA/BC7 from the Langmuir equation were 20.28 mg?g-1 and 35.46 mg?g-1 at pH=5. The adsorptions of Cu(II) by the BC7 and CA/BC7 were in good agreement with pseudo-first-order model, which suggested that the rate limiting step was governed by diffusion. Mechanism studies for Cu(II) removal by BC7 showed that the nature of Cu(II) abstraction took place through the formation of Cu(II)-O-Si and Cu(II)-Complex. The Cu(II) removal by the CA/BC7 were mainly through the ion exchange between Ca (II) and Cu(II) as well as the formation of coordination complex.