Abstract: Since ocean nuclear power plants are the mainstay of the offshore energy supply of the future, their operational environments differ greatly from those of conventional land-based nuclear power plants. The reactor system’s flow and heat transfer properties are significantly altered because it is constantly subjected to complicated motion conditions including rolling and heaving motion. The integrity of fuel cladding and core meltdown avoidance are directly related to critical heat flux (CHF), a key measure used to calculate the thermal safety margin of nuclear reactors. A significant technical barrier preventing the safe design of ocean nuclear energy systems is the fact that the majority of CHF research is limited to land static conditions, and knowledge of the boiling heat transfer mechanism of two-phase flow under six degrees of freedom motion is woefully inadequate. A high temperature and pressure CHF experiment bench under six degrees of freedom motion (PERFORM) to overcome the aforementioned difficulties was built in the paper. By contrasting the experimental data of static conditions with the anticipated value of the LOOK-UP-TABLE, a round tube test section was utilized in this work to verify the precision and dependability of the test loop. To determine the mechanism by which ocean motion conditions affect CHF, CHF tests covering various motion modes, including inclined, heaving, and rolling, were conducted under stringent error control. The penalty factor ranges from −5% to 5%, and the inclined condition’s impact on CHF is not readily apparent, but it may cause CHF to rise or fall. The penalty component varies between 2% and 14.3%, and the CHF falls under the rolling conditions. Most of the time, heaving conditions cause CHF to decline, and the penalty factor is between −5% and 6%. Based on the experimentally revealed multi-physics coupling mechanism of CHF under motion conditions, this study creatively builds a multi-scale numerical simulation system that combines Euler’s two-fluid model with the Rensselaer Polytechnic Institute (RPI) wall boiling model. At the macroscopic level, the turbulent velocity field and pressure field are solved using Reynolds mean Navier-Stokes (RANS) equations, which are then closed using the realizable k-ε turbulence model. A comprehensive model of momentum exchange was developed to accommodate the shift in drag characteristics brought on by bubble deformation under moving conditions. This model includes drag force, lift force, virtual mass force, and turbulent dissipation force. Using this strategy, the average absolute error between the experimental data and the calculated value is essentially less than ±10%. These techniques offer the required data support and a trustworthy prediction method for the critical heat flux features under motion conditions.