A rear end of a main body of a rack body with an airflow blocking mechanism is pivotally coupled to a blocking sheet, and the blocking sheet is adjusted to be levelly or erectly disposed conveniently; the position change of the blocking sheet is relied on to control air to flow into a rack body or not to allow the rack body installed with no electronic device in the same computer housing to have an airflow blocking function to avoid decreasing air amount flowing through other rack bodies installed with an electronic device so as to elevate the electronic device cooling efficiency.