The invention discloses a method for predicting the remaining lives of bearings. The method comprises a step of collecting first temperature data of a first bearing during a whole service process and calculating a first fault index according to the first temperature data, a step of establishing a relationship between a fault index and a run mileage of a bearing according to the first fault index and a run mileage corresponding to the first bearing, a step of subtracting the run mileage of the bearing from a design life of the bearing to obtain a bearing remaining life, and thus establishing a relationship between the fault index and the remaining life of the bearing, and a step of substituting a second fault index of the second bearing into the relationship between the fault index and the remaining life of the bearing to obtain a remaining life of the second bearing. According to the method, the remaining life of the bearing during a running process can be predicted, the bearing health is taken into account, and the access of an overhaul section for maintenance is not needed. The invention also discloses a device for predicting the remaining lives of bearings.