Building block of building outer protective wall

The invention provides a building block of a building outer protective wall. The building block comprises a first block body, a second block body, an outer heat preservation layer, an inner heat preservation layer, a connecting component, a top plate, an inserting rod, a clamping plate, a buckle, a buckle main body, a bending part and a clamping part, the first block body and the second block body are each internally provided with an outer heat preservation layer. The inner heat preservation layer is installed between the first block body and the second block body, and the two sides of the inner heat preservation layer are clamped and fixed to the first block body and the second block body respectively. The first block body and the second block body are fixed through a connecting component; by improving the building block of the building outer protective wall, the building block has the advantages of being reasonable in structural design, good in heat preservation effect, convenient to divide and operate, hig