Tungsten has been considered as one of the most promising candidates for plasma-facing materials in next-step fusion energy systems. The helium and hydrogen bubbles lead to the serious damage of structure and degeneration of thermal and mechanical properties of W. It is still difficult to reveal the physical mechanisms of interaction between radiation defects and helium/hydrogen by using experimental skills, however, the multi-scale computation and simulation are more effective. Based on the progress of different computation and simulation methods in recent years, this paper systematically introduces the effect of the defect type, concentrations, size, distribution and temperature. Meanwhile, the binding energy, formation energy, diffusion path, diffusion barrier, clustering bhaviors and microstructure evolution are discussed. In the end, the existing key scientific problems and development trend are pointed. The results are contributing directly to the design, preparation and application of W based materials under a fusion environment.