The invention relates to the field of machinery, in particular to a wear-resistant environment-friendly low-energy-consumption 8-shaped rotor engine as well as a rotor and an acting method thereof. The engine comprises a cylinder body, an inner shell space with three arc-shaped surfaces being in butt joint is contained in the cylinder body; the engine further comprises a rotor capable of rotatingin the inner shell space, and the rotor is of a structure similar to an 8-shape; the engine further comprises a shaft penetrating through a hole inside the 8-shaped rotor, and the shaft is an eccentric shaft; the rotating part of the eccentric shaft can drive a rotating structure of the structure similar to the 8-shape in the inner shell space; and the inner shell space comprises an oil hole. Firstly, the problem that a traditional rotor engine is unreasonable in structure is solved; secondly, the problems that the traditional rotor engine is low in compression ratio and limited in types of available fuels are solved; thirdly, the problems that for the traditional rotor engine, the combustion is incomplete, due to oil burning, pollution is serious, and emission does not reach the standardare solved; and fourthly, the problems that the traditional rotor engine is serious in abrasion and short in service life are solved.