Abstract: Accelerator Driven System（ADS） will be a transition between the current nuclear system and the complete application of fusion energy.Because the maintain of power level in ADS relies on the neutron source generated through intensive proton beam hitting spallation target,the instability of proton beam as well as trips in any form will influence the reactor power level and further the safety of ADS.Currently,the research of trip problem is becoming internationally a hot issue in ADS research.Beam transient change accident in ADS is extensively studied in this paper,and the physical and mathematical simulation models is established.Finally,the special software-SIMULINK-ADS dedicating to ADS beam transient change accident is designed and developed.Through the analysis of typical beam transient change accident,simulation results are obtained and recorded,which tally satisfying with the results of OECD/NEA and FZK Karlsruhe research institutions.The results show that SIMULINK-ADS can effectively compute and analyze the sub-critical physics and transient thermal-hydraulic characteristics of ADS.