The invention relates to the technical field of electronic equipment and provides an equipment cabinet and a modular data center. The equipment cabinet comprises a top plate, a bottom plate, and multiple side plates. The multiple side plates cooperate with the top plate and the bottom plate so that the equipment cabinet with box structure is formed. A receiving space is arranged in the equipment cabinet and is used for receiving a functional module. The multiple side plates comprise a first side plate and a second side plate which are arranged oppositely. Along the direction from the first side plate to the second side plate, a ventilating channel is formed at least one side of the receiving space. A position, used for forming the ventilating channel, of at least one of the others of the multiple side plates is provided with a ventilation opening that can be opened or closed. By opening the ventilation openings on corresponding side plates of the equipment cabinet, the ventilating channel formed in the equipment cabinet can be communicated with the ventilating channels of other equipment cabinets so as to form a closed ventilation channel. The equipment cabinet is not required to be provided with other accessories, is easy to assembly, and is simple in structure after being assembled.