A novel foam metal magnetorheological fluid (MRF) damper was designed.By using the foam metal as a storage carrier of MRF,the magnetorheological fluid can be sealed in the damping chamber,which has a good solution to the high cost and difficulty resulted from sealing magneto rheological fluid in the traditional damper.A finite element simulation of magnetic field for the damper was carried out.The uniform magnetic field distribution of the damper proves that the structural design is reasonable.A PID semiactive vibration control system was developed according to the novel damper,and a vibration damping experiment of cantilever beam was performed.The experimental results show that the metal foam MRF damper has the merits of rapid response on controlling signal and good damping controllability,indicating that the metal foam MRF damper has an advantage in using in semi active control system.