Network crown ether resin with the pendent sulfur ether group was prepared by ring-opening copolymerization of 3-thiopentyl glycidyl ether and diethylene glycol bisglycidyl ether with Na, NaOCH2CH2OCH2CH2OH, or BuLi as catalyst, respectively. The yield of network polymer and the conversion of functional monoepoxy monomer are varied from catalyst to catalyst, and the thermostability of the resin is related to the content of the sulfur ether group. The resins show high adsorption capacity toward Cu(II), Pb(II), especially, Hg(II) ions, but poor adsorption capacity toward Mg(II) ions. Corresponding thermodynamic parameter of Hg(II) ion was deduced, and could be expressed approximately with the Freundlich equation.