The traditional numerical methods for simulating the dynamic response and progressive collapse of entire structures require complicated modeling work and extremely time-consuming calculation, resulting in their rare application. In this paper, a new method for the numerical analysis of entire structural model is proposed, which is directly employed to analyze the dynamic response and damage patterns of steel frame structures subjected to blast loads. According to the new method, the simulation process is divided into two steps. Firstly, the propagation of blast wave in air is simulated by the Remap tool of AUTODYN. The numerical gauges are used to record the pressure time history on the surfaces of structural members, e.g. columns and beams. Secondly, a refined finite element model of steel frame structure is created, and the blast load is applied on the surfaces of members according to the measured data in the first step for further analysis of structural response and damage procedure using the explicit solver of LS- DYNA. The whole simulation of structural response of a typical steel frame structure caused by blast load is carried out. The numerical results show that the steel frame structure is capable of resisting blast load, which is adequate to survive a medium-scaled （ up to 1 000 kg equivalent of TNT charge） out-door explosion. Severe progressive collapse or local damage as downfall of secondary beam is likely to be induced by a huge-scaled blast load case （more than 1 500 kg equivalent of TNT charge）.%传统数值方法模拟建筑结构在爆炸荷载作用下的结构响应和连续倒塌时，具有计算模型复杂、计算量大的特点，实际应用价值不大。基于将爆炸荷载作用下结构响应分析分两步进行的数值模拟方法，利用非线性显式动力分析软件AUTODYN的Remap技术模拟爆炸波在空气中的传播过程，利用压强测点记录结构构件表面的爆炸压强时程曲线；建立结构精细化有限元模型，并将上一步记录的爆炸压强时程曲线施加于结构构件，利用LS—DYNA显式求解器分析结构在爆炸荷载作用下的动态响应和倒塌过程。将该方法应用于某钢框架结构在爆炸荷载作用下的动态响应和连续倒塌分析。结果表明：钢框架结构具有较好的抗爆性能，在发生1000kgTNT当量及以下规模的室外爆炸时，主体结构能够保证安全；在发生1500kgTNT当量及以上大规模爆炸时，发生次梁塌落等局部破坏，亦可能发生结构连续倒塌。
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