In view of the special requirements of the operating pressure and layout of the tubular separation system of an unmanned production platform in a marginal oilfield, a support frame design scheme is presented, and the static analysis, modal analysis and transient analysis are carried out by finite element method to explore the static and dynamic mechanical properties of the tubular separation system-supported frame. The results show that: the design scheme of the support frame meets the requirements of static stiffness and strength; the characteristic frequency of the whole structure is not lower than 6.9 Hz, which is much higher than the intrinsic frequency of the slug flow inside the pipeline; although there is a dynamic amplification effect, the deformation and stress of the structure meet the requirements of dynamic stiffness and strength under the slug flow impact.