Abstract: In order to improve the working reliability of wire-line coring drilling tools used in submarine drilling rigs, based on the particularity of submarine environment, from the aspect of improvement of the single action performance of the single action mechanism and the working reliability of the suspension mechanism, the structural optimization of the single action mechanism was carried out, the numerical simulation analysis of the suspension mechanism was conducted by using ABAQUS simulation. The results show that the improved bearing assembly structure can restrain sea water corrosion, improve the centering effect of arbor and enhance the flexibility of bearing assembly. The improved suspension mechanism can reduce the risk of plastic deformation of key parts used frequently, enhance the working reliability of suspension mechanism. This research results can provide theoretical foundation for related drilling tool design.