Disclosed is a waterproof structure of a cold aisle cabinet. The waterproof structure of a cold aisle cabinet includes a cabinet group which includes a plurality of cabinets, a first covering plate parallelly defined above the cabinet group, and a support frame defined between the first covering plate and the cabinet group, the support frame being mounted on the cabinet group and abutting against the side of the first covering plate facing the cabinet group; the area of the top surface of the first covering plate is larger than or equal to the area of the top surface of the cabinet group.