The invention provides a motor rotor shaft penetrating device. The motor rotor shaft penetrating device comprises an iron core fixing component and a rotating shaft pushing component, wherein the rotating shaft pushing component is used for pushing a rotating shaft therein; the iron core fixing component is used for fixing a rotor iron core; the iron core fixing component is located in the pushingdirection of the rotating shaft pushing component; when the rotating shaft pushing component pushes the rotating shaft, the rotating shaft can be arranged in a rotating shaft hole formed in the rotoriron core in a penetrating mode. According to the motor rotor shaft penetrating device disclosed in the invention, the shaft penetrating process of the rotor iron core is realized in a mechanical mode, so that the automation degree is high, the working efficiency of the rotor shaft penetrating is greatly improved, the working difficulty is lowered, and the labor cost can be saved.