Because the maintain of power level in Accelerator Driven System (ADS) relys on the neutron source generated through intensive proton beam hitting spallation target, the frequent beam trips will influence the subcritical reactor safety of ADS. Beam trip accident characteristics in ADS is studied in this paper, and the special software - SIMULINK-ADS dedicating to ADS beam trip accident is designed and developed. The dynamic characteristics of accelerator-driven fast neutron breed subcritical reactor is Preliminarily researched. At last the di...