The present utility model provides a magnetic building block. A building block back side is installed on a rear end of a building block front side. Four notches are formed on both of the rear end of the building block front side and a front end of the building block back side. Four protruding chucks are formed on both of the rear end of the building block front side rear end and the front end of the building block back side. Four small magnets are disposed on the front end of the building block back side. The protruding chuck and the notch are disposed on two sides of the small magnet. An embedded paper is disposed between the building block front side and the building block back side. The embedded paper is inlaid in a rectangle surrounded by the notch, the small magnet, and the protruding chuck.