BeiDou Navigation Satellite System (BDS) B2a signals transmits on the Air Radio Navigation Service (ARNS) band from 960 to 1215 MHz, in which there are ground-based radio navigation signals that may cause unintentional interference with BDS signals. Among the signals in BDS B2 frequency bands, the frequency range of B2a signal is completely covered by Distance Measurement Equipment (DME) and Tactical Air Navigation System (TACAN) signals. In this paper, we use the simulation DME beacon database to analyze the DME interference hotspots in mainland China. By studying the characteristics of DME pulse signals and improving the original model proposed in Radio Technical Commission for Aeronautic (RTCA) DO292 file, we then evaluated the effects of the pulse signals transmitted by DME beacons on the BDS B2a band within China hotspots. In this paper, a set of DME interference simulation testbench is built. The performance gains from the improvement of the collision model and the necessity of using DEM is demonstrated through the experiments conducted on our testbench.