Doping heteroatoms into carbon matrix was an efficient strategy to achieve a high-performance non-precious metal oxygen reduction electrocatalyst. Herein, an in situ templated synthesis strategy has been demonstrated to fabricate nitrogen, sulfur and iron-tridoped mesoporous carbon nanosheets(NSFC) with FeCl3 as the two-dimensional template. And a protic salt was used as the carbon, nitrogen and sulfur source, which realized one-step preparation of catalyst materials and the co-doping of various heteroatoms simultaneously. As a result, the optimized NSFC catalyst possessed comparable catalytic activity and selectivity, while superior durability and methanol permeability resistance to commercial 30 wt% Pt/C catalyst in alkaline media. Such excellent performance should be ascribed to the efficient multiple-element doping into the large-specific-surface-area and highly stable carbon nanosheets realized by the in situ synthesis route with a novel FeCl3 template.