Connecting structure of building block toy

The utility model relates to a connecting structure of a building block toy, which comprises a spherical clamp head arranged on a building block and a connecting block arranged on the building block, wherein a slot in fit with the clamp head is arranged in the connecting block. The building blocks can be connected to be an integer and each component can be freely rotated in various directions; the toy can be used for exercising the practical ability of the children, improving flexibility of fingers of the children and developing independent creativity and imagination of the children.