Abstract: Accelerator beam transients induced by the instability of the High Power Proton Accelerator（HPPA） will lead to the rapid intensity change of the spallation neutron source, which will impact the safety of subcritical reactor of ADS. The dynamic characteristics of the subcritical reactor in the beam transients is an important issue of ADS safety. In this paper, based on the brief summation of previous research works, the primary calculation and analysis related to beam transients have been carried out on the ADS verification facility "VENUS1#". Based on the results of "VENUS1#", the real-time calling multi-mode parameters in ADS beam transients analysis is suggested.