The invention relates to an apparatus and a method for measuring the secondary electron yield of a metal material within a low energy range. The apparatus comprises a collection pole, two ammeters andan electron gun, wherein the collection pole has two layer and has a downward opening, the top portion of the structure of the collection pole is provided with a reservation hole, the upper surface of a sample is placed in the collection pole and is positioned just below the reservation hole, the electron gun shoots incident electrons onto the sample through the reservation hole, one ammeter as the ammeter A is connected between the sample and the ground, the other ammeter as the ammeter B is connected between the inner surface of the collection pole and the ground, and the outer surface of the collection pole is grounded.