To investigate the suppression performance of the spar-type wind turbine vortex induced motion(VIM) with the addition of splitter plate, VIM model tests were carried out in a circulating water channel. Two different splitter plates width conditions were tested. In all the conditions, the cylinder was free to oscillate with one DOF. Results regarding response amplitudes and characteristic frequencies were presented and discussed. There was no obvious lock-in phenomenon on the vortex excitation motion of the cylinders with splitter plate, only some synchronization was observed. W/D=0.2 has better suppression performance than W/D=0.4 in vortex induced motion.