Abstract: Resistance of underwater explosion shock wave has been a knee research subject of naval shipbuilding industry for decades. Major research topics focus on ship structure resistance. For naval vessels equipped with nuclear reactor, few researches are available to showcase the overall design, test and sea trail processes. The scarcity of such literature however doesn’t negate the importance of necessary investigations, despite the sensitivity of its application background. That is to say, shock resistance of marine nuclear reactor is a key dimension that determines nuclear safety. During the nuclear safety review, naval users usually concern two aspects regarding the reactor shock resistance capability: 1) Shock load environment of reactor system and equipment that can represent the underwater explosion scenario submarine undergoes under combat situation; 2) Compatibility of shock resistant design load and onshore shock test load. A thorough yet costly response of the above-mentioned concerns is to conduct full scale shock trail of the whole ship with vital systems onboard, preferably at operation conditions. This is what US Navy has been conducted over the last 60 years for perhaps the majority if not all newly types of enlisted naval vessels. From a more practically and cost saving perspective, upon answering these two questions, this article first established the load prediction method of reactor system subject to underwater explosion. Computational code was developed based on domestic finite element analysis platform and was verified by scaled model test. The code was backboned by finite element method on structural side and boundary element method on fluid side. It accounts the coupling of incident shock wave on wet surface and suits the application for both surface and fully submerged vessels. Using this code, the authors simulated the shock load prorogation mechanism of a specific reactor system with the model accounts for the interactions among hull, support, raft and heavy equipment. The simulation yielded the design shock load of key equipment at interface locations. In addition, we developed the virtual test rig of medium size swing shock machine. Verification of this virtual test rig was conducted and the design-test load compatibility of nuclear fuel assembly was studied. Parameter setup of the onshore shock test was acquired that can match the design load of the fuel assembly. Other mission critical equipments in the reactor system, including the control rod drive mechanism, pumps, valves, piping supports, etc. can also follow this procedure to acquire compatibly offshore load conditions in order to test their functions under the utmost real life combat scenario, which to the authors’ best knowledge, are way beyond today’s most state-of-art simulation technology to be studied. The research reported herein unifies the shock design and onshore test load. It also provides technical support of future product develop that considers shock load under real combat scenarios.