The invention relates to technology for separating polyethylene from methylbenzene and recycling the polyethylene and the methylbenzene in preparation of superfine fibers. The technology comprises the following steps of: (1) evaporating polyethylene-containing methylbenzene solution by a pre-evaporator till the methylbenzene accounts for less than 50 percent based on the weight of the polyethylene-containing methylbenzene solution; (2) evaporating by a first horizontal tube evaporator till the methylbenzene accounts for less than 15 percent based on the weight of the polyethylene-containing methylbenzene solution; (3) evaporating by a second tube evaporator till the methylbenzene accounts for less than 1 percent based on the weight of the polyethylene-containing methylbenzene solution; (4) condensing and recycling the methylbenzene vapors obtained in the steps (1), (2) and (3); and (5) pelletizing the polyethylene obtained in the step (3). The corresponding device for separating the polyethylene from the methylbenzene and recycling the polyethylene and the methylbenzene comprises the pre-evaporators, a condensing device, a polyethylene relay groove, the first horizontal tube evaporator, the second horizontal tube evaporator, a first gear pump, a second gear pump and a vacuum system. The processing capacity of equipment is about twice that of the prior art, and the equipment can operate continuously, so that the methylbenzene content in the polyethylene is reduced, the separation effect of the methylbenzene and the polyethylene is improved, and environmental pollution is reduced.