Abstract: A dual-rotor engine comprises a cylinder assembly, a transmission output mechanism, a rotor control mechanism and a lubrication system. The cylinder assembly comprises a tubular cylinder (6) and two rotors (1a, 1b). Each of the rotors (1a, 1b) comprises an inner cylindrical cylinder (99a, 99b), a rotor journal (20a, 20b) integrated with the inner cylindrical cylinder (99a, 99b) and two sector pistons (17a, 17b) symmetrically secured to the inner cylindrical cylinder (99a, 99b); four sector pistons (17a, 17b) of two rotors (1a, 1b) are arranged crosswise to each other, and two adjacent sector pistons (17a, 17b) form a combustion chamber. The transmission output mechanism comprises two rotor gears (2a, 2b) and two driving gears (3a, 3b) which engaged with each other respectively.