The invention relates to a harmless energy recycling and treatment system for wastewater of a road tanker washing station, which comprises an anaerobic reaction tank, an oil separation tank, a coagulation tank, an aerobic reaction tank, a sedimentation tank, a Fenton reaction tank, a recycled water tank, a washing unit, a domestic wastewater collection tank, a septic tank, a methane bag and a heating boiler, wherein the anaerobic reaction tank comprises an anaerobic reaction barrel and an interlayer outside the anaerobic reaction barrel. The invention further discloses a harmless energy recycling and treatment method for the wastewater of the road tanker washing station. The system and the method disclosed by the invention can be used for treating washing wastewater, domestic wastewater and septic tank wastewater produced by the road tanker washing station together, and effectively solving the problem of fuel needed by the heating boiler of the washing station, moreover, the residual heat of washing water is sufficiently utilized, and the objective of wastewater recycling and the objective of zero emission are achieved.