A cargo bracing device includes a fixing member and a driving member. Mainly the fixing member possesses a connecting plate easily fitted with one end of an elastic device, and a locking plate easily fitted with another end of the elastic device. So the locking plate can be restored with dynamic force provided by the elastic device deposited between the connecting plate and the locking plate. The driving member includes two wings respectively having one end formed as a hook collaborating with a latch of a driven plate to enable the driving member combined with or detached from the fixing member. Similar to the fixing member, an elastic device is easily installed between an actuating plate and a connecting bar of the driving member, providing dynamic force for restoring the actuating plate. Therefore the cargo bracing device can be easily assembled, even with automatic equipments.