Abstract: Firstly, using m-aminobenzoic acid as raw material, m-carboxyphenyl azo calix4arene derivative was synthesized by upper-rim modification of calix4arene through diazotization-coupling reaction. Then, a new material called m-carboxyphenyl azo calix4arene symmetrical sulfide derivative was synthesized by substitution reaction. The new material was characterized by FT-IR and ¹H-NMR. It was used to adsorb U(Ⅵ) of the low concentration uranium-containing aqueous solution. The effects of initial pH, dosage of adsorbent, initial concentration of U(Ⅵ), time and temperature on the adsorption of U(Ⅵ) by the adsorbent were investigated. The results show that when the initial concentration of U(Ⅵ) is 10 mg/L, the initial pH is 4, the temperature is 25 ℃, the contact time is 4 h and the dosage of adsorbent is 10 mg, the adsorption effect of U(Ⅵ) by m-carboxyphenyl azo calix4arene symmetrical sulfide derivative is optimum. Its adsorption process conforms to the pseudo-second-order reaction kinetic model, indicating that the adsorption is chemisorption. Its adsorption isotherm is consistent with the Langmuir isotherm model, indicating that the adsorption system is based on single-layer adsorption. The above results indicate that m-carboxyphenyl azo calix4arene symmetrical sulfide derivative is a potential uranium adsorbent.