The invention discloses an engine assembly integrated with a retarder. The engine assembly integrated with the retarder is characterized in that the engine assembly comprises an engine body and the retarder; the engine body comprises a shell, a crankshaft, a crankshaft extension part and a flywheel; the retarder comprises a stator and a rotor and is arranged between the flywheel and the crankshaft extension part; one end of the crankshaft extension part is connected with the crankshaft, and the other end of the crankshaft extension part is connected with the flywheel; the stator is fixed to the shell, and the rotor is in rigid connection with the crankshaft extension part. The invention further discloses a vehicle comprising the engine assembly integrated with the retarder. According to the engine assembly integrated with the retarder, the overall arrangement of the retarder is improved, and thus the installation cost of the retarder is reduced, and convenience is provided for serial installation of the retarder.