Abstract: The mechanical simulation model of vertical vibration of Marine riser under suspension mode has been established based on the basic principle of dynamics theory. In the model, the influence of heave movement and top tensioner is considered. The vibration equation is solved by the finite difference method to obtain the distribution of axial stress and displacement. Besides, the effects of suspension mode, buoyancy block,water depth, wall thickness and LMRP on the vertical vibration of riser are discussed. According to the results, the soft suspension mode is superior to the hard suspension mode. The buoyancy blocks will increase the axial vibration of the marine riser. The axial displacement and stress of the riser first decrease and then increase from the top to the bottom, and the variation tendency of increase of bottom decreases gradually with the increase of water depth. The riser axial displacement and stress gradually decrease as wall thickness increases, and the stress of riser increases with the increase of LMRP mass.

Key words: marine riser, suspension mode, vibration characteristics, simulation model, finite difference method