A coupling structure includes a main board and at least one coupler detachably connected to the main board. The main board has at least one coupling trough defined in the main board, a first abutting element defined in a side face of the at least one coupling trough and a support beam formed adjacent to the at least one coupling trough. The at least one coupler has at least one first arm and at least one second arm to receivably contain therebetween the support beam. The at least one first arm has a second abutting element formed at a distal end thereof to correspond to and abut a periphery of the first abutting element so that engagement between the main board and the at least one coupler is detachably secured.