The Ti/SnO2-Sb electrode with/without Er were manufactured by Pechini’s method. The electrodes were characterized using SEM, EDS, XRD, FT-IR, the oxygen evolution potential test and their electro-catalytic abilities were evaluated though nitenpyram degradation. XRD and FT-IR results showed that the structure of the electrodes were Sn-base sosoloid without Er and Sb phases. The Er3+ iron entering the unit cell of SnO2 (Sn4+) could cause the grain refinement, the surface enrichment of Sb and Er, stronger water absorbability, and higher anode potential. These consequently generated more active sites and less oxygen vacancies on the anode surface, leading the improving of the electro-catalytic performance. The grain refinement mechanism for Er doping may be ascribed to the increase of the surface composition supercooling, the acceleration of the SnO2 generation rate, and the restrain of its growth rate.