The mobile wellhead platform has the characteristics of being movable and reusable， and it is mainly used for the development of marginal oilfields. The platform is supported by four pile legs. Due to the lack of a supporting structure for the subsea pipelines and cables， it is impossible to board the platform with the jacket as the supporting structure like in a jacket platform.The advantages and disadvantages of three types of boarding methods relying on the wellhead riser， the liftable pipe rack， and the pile legs are analyzed. Boarding relying on the pile legs has advantages such as being liftable， reusable， having little impact on the platform's performance， and having a simple system. However， it is necessary to address the impact of the boarding riser passing through the platform's enclosure area on the structure and the occurrence of vortex-induced vibration phenomena. Analyzing and researching the vortex-induced vibration of the boarding riser provides a theoretical basis for the vibration control of the riser.