Abstract: In order to eliminate the deviation between explosion test and numerical simulation, the pressure distribution of blast wave on the surface of concrete filled steel (CFST) column had been analyzed by executing the explosion test. And by using FEM procedure and considering the condition of explosion test, a FEM model of CFST column had been established. In order to investigate the influence of the different mesh size of air and explosive on the blast wave propagation and pressure value of blast wave, the numerical simulation with the different mesh size of air and explosive had been executed based on explosion test results. Analysis of research results shows that the constraints of column are in good condition and deformation of column belongs to elastic stage when the scale distance is 1.1 m/kg1/3in explosion test. Both peak pressure value and positive impulse value should be considered together in evaluation of damage on column. The different mesh sizes of air and explosive have great impacts on the peak pressure of blast wave and the trend of pressure-time curve. And the results of numerical simulationcorrespond with the test results well when the mesh density of air and explosive increases. Finally, by examining the accuracy of the numerical results and comparing with the test results, the mesh size of 20 mm is considered to meet the requirements of numerical simulation when the scale distance is not less than 1.1 m/kg^1/3.