The wellhead suction module is one of the key equipment of riserless mud recovery drilling （RMR） system，and the status when working on the seabed has a certain impact on the drilling work. In this paper， an open wellhead suction module is designed， a three-dimensional model is established， morison equation is used to calculate the internal wave current load， the P-y curve method is used to simulate the spring equivalent of the soil conditions， and the wellhead suction module is analyzed statically and modally. The research shows that the displacement of wellhead equipment is greatly reduced compared with that of the normal deep-water drilling， and the stress and strain of suction module and its connecting parts are smaller when using RMR drilling technology. The intrinsic frequency of wellhead suction module is obtained from the modal analysis of wellhead suction module， which provides referencial value for the size optimization of wellhead suction module and the application of the RMR technology， and provides technical support for drilling to deep ocean.