The purpose of this thesis is to investigate the control effect of a semi - active vibration absorber developed for an offshore platform and a vibration control system is also designed . the vibration of the structure is suppressed by installing the new and innovative variable stiffness tuned mass damper ( vstmd ) on the top deck of the platform 计算表明,本控制装置对由随机波浪载荷引起的平台振动有一定的控制效果,对平台甲板加速度响应的控制效果最高可达29 ,其平均效果也在21以上,甲板的位移响应也能得到一定的抑制。