Based on the discrete phase model, the trapping performance of fiber layers with different arrangement structures under two trapping mechanisms of interception and inertial impaction was simulated by numerical simulation method. The effects of particle diameter, inlet velocity and fiber layer filling rate on the trapping performance of fiber layers with different arrangement structures were analyzed. The results showed that large particle size particles with inertial impaction as the main trapping mechanism were more easily affected by the arrangement structure of fiber layers. The vertical arrangement structure effectively improved the trapping performance of large particle size particles by fiber layers, and the trapping performance showed a trend of increasing first and then decreased with the increase of particle diameter. The trapping efficiency of fiber layers with different arrangement structures for large particle size increased with the increase of inlet velocity. The trapping efficiency of fiber layers with single-layer vertical arrangement structure was higher than that of the other two arrangement structures, and its trapping performance decreased with the increase of inlet velocity. The trapping efficiency of fiber layers with different arrangement structures increased with the increase of filling rate, while the trapping performance decreased with the increase of filling rate. Compared with the fiber layers with the three arrangement structures, under the conditions of low filling rate and low inlet velocity, the single-layer vertical arrangement structure fiber layer had the most obvious improvement in the trapping performance of large particle size particles. The single-layer vertical arrangement structure fiber layer had the highest trapping rate for particulate matter.