Abstract: The anode coatings for IrTaSnSb oxide were prepared with precursor solutions of different concentrations by thermal decomposition method. The surface morphology was observed by scanning electron microscopy. The chlorine evolution activity of anodes was tested by electrochemical method, and the current efficiencies in sea water at room temperature and low temperature and brackish sea water were tested. The lifetime of the IrTaSnSb anode coatings were measured by accelerated life test in H₂SO₄ solution. The results show that there are significant differences in the surface morphologies of the anodes prepared by precursor solutions of different concentrations, and the chlorine evolution activity of anode arises and then decreases as the solution concentration increases from 0.05 mol/L to 1.00 mol/L; the anodes prepared by 0.30 mol/L solution have the highest chlorine evolution activity, for the tiny and uniform cracks in the anode surface increase the real active surface area and improve the chlorine evolution activity; when the loadings of anode coating is close, the anode surface coated by solution of low concentration is even and dense, the surface of titanium substrate is hard to be oxidized to form TiO₂ passivative film, and the anodes exhibit high life time. The anode prepared by 0.30 mol/L precursor solution shows high chlorine evolution activity and long life time, and 0.30 mol/L is an ideal concentration of precursor solution.