The invention discloses a hub unit check block press-fitting method and a device thereof. The method includes the steps that an inner flange of a hub unit is arranged on a unit bottom die above an axial pressurizing air cylinder, the pressurizing air cylinder acts to drive the hub unit to ascend, and when an outer flange of the hub unit tightly presses a unit upper die above the unit bottom die, the axial pressurizing air cylinder stops ascending; a check block is placed in check block pressing plates on the two sides of the unit upper die, a radial air cylinder on the outer side of a check groove stretches out inwards, the check block is press-fit in a check block groove of the inner flange, and automatic press-fitting of the check block is achieved. The hub unit check block press-fitting method and the device thereof have the advantages of achieving automatic machining and being high in machining accuracy and good in stability.