A block strengthening air enclosure comprises a plurality of air cylinders, a plurality of nodes disposed on the plurality of air cylinders to allow the plurality of air cylinders to be bended along the plurality of nodes to form an accepting space, and at least one sheet positioned in the accepting space and attached onto a bended part of the plurality of air cylinders. After the plurality of air cylinders are filled with air and expanded, the accepting space can then be used for accepting an article, and the pat or block of the plurality of air cylinders needed to protect is strengthened through the sheet. Whereby, the air cylinders can be prevented form being piecing through and broken by a part of the article such as a projecting face, angle or edge; the production cost can be reduced, more kinds of articles can be accepted in the accepting space and the use convenience can be elevated.