An equal proportion separated common node model was established by ANSYS/LS-DYNA finite element software to simulate the collapse process of a frame structure with a small height-width ratio demolished by blasting,and the stress characteristics of reinforced concrete columns of the structure were analyzed.It is found that the actual engineering and simulation results are highly consistent in terms of collapse time,collapse process and blast muck pile range,which shows that the numerical simulation is reliable.Additionally,during the collapse process,the plastic hinge was generated at the beam-column joints after each row of columns reached the section resistance moment,and the upper structure rotated with the plastic hinge as the fixed axis.There was a backward reaction force on the rear column,which resulted in an obvious recoiling in the forward leaning process.In the early stage of collapse,the stress of the reinforcing bar and the concrete element is stressed together.The stress of the reinforcing bar element with its co-node suddenly changed after the failure of the concrete element,and then it continuously changed in the state of tension and compression until the collapse ended.The reinforced bar at the blasting cut has certain hindrances to the free fall of the upper structure.