Method for constructing USB composite equipment during running in embedded system

The invention discloses a method for constructing USB composite equipment during running in an embedded system. The same attributes of different Class of the USB are abstracted; object-oriented thought, a plurality of objects under different classes can be constructed; zero coupling between different objects is realized; no matter during the equipment enumeration period, the equipment is enumerated; or in the communication process of the non-control endpoint, the USB cores can find specific objects of corresponding equipment classes through abstract attributes. Therefore, the further processing of the Class protocol level is realized; such a method, if the system wants to be expanded into three virtual serial ports on the basis of two original virtual serial ports, the system can be expanded into three virtual serial ports. According to the method, only one function needs to be called to add one class of equipment, so that compared with the mode that other USB driver stacks only support one equipment class or