Two-dimensional district element model (DEM) was used to analyze the deformation behavior of pure molybdenum powder material during single pass of equal channel angular pressing (ECAP) in the view point of mesoscopic. The variations of load, particle and pore of the sample during ECAP processing were obtained. The simulation results indicate that ECAP is an effective technique to eliminate the porosities. Based on the results, the whole deformation process can be divided into four stages: particle re-arrangement, initial deformation, transitional deformation and steady deformation. District element analyses show that the high hydrostatic stress and large plastic shear strain value densify the powder material by reducing the number of large pores, closing the little pores and deformation of particles and pores. In addition, the experiment results of pure molybdenum powder materials in copper tubes of single pass ECAP under a temperature of 400 ℃ have good consistency with the simulation ones, which gives a powerful evidence to support the established district element model.% 采用离散元分析软件 PFC-2D 对纯钼粉末材料的单道次等径角挤压过程从细观角度进行数值模拟，获得其变形过程中载荷、颗粒和孔隙的变化规律。模拟结果表明，等径角挤压对粉末材料具有强烈的致密化作用，且整个变形过程可以分为4个阶段：颗粒重排、初始变形、过渡变形和稳定变形。分析认为，冲头压力首先使颗粒重排减少大孔隙，之后，由于压力增大使小孔隙闭合，剪切作用使颗粒和孔隙发生变形，结合强大的静水压力使材料致密。在400℃条件下的纯钼粉末−黄铜包套单道次挤压实验结果与模拟结果具有较好的一致性，验证了所建离散元模型的可靠性。
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