Abstract: Based on the unique design characteristics and safety features of Xi'an Pulsed Reactor (XAPR), the special key techniques of XAPR probabilistic safety assessment (PSA) was studied. XAPR PSA analysis framework and the way to implement the key technique were put forward. Finally, XAPR PSA research thought was illustrated by a case study on medium LOCA at the core height of XAPR reactor pool. The analysis shows that the integral event tree framework, which spread through event sequence structure with initiating events at the beginning and radioactive release categories in the end, is suited to XAPR PSA analysis at this stage.