The effects of symmetric strips on the flow-induced oscillation (FIO) of a cylinder in a uniform flow are investigated numerically. A pair of symmetric smooth strips are attached parallelly to a cylinder at different angles α from the frontal stagnation point. One degree of freedom cylinder movement is only allowed in the direction perpendicular to the incoming flow. The vibration is suppressed for α = 30°, and galloping is observed for α = 60°. Regarding wake dynamics, the vortex shedding in the galloping range is significantly different from the traditional vortex-induced vibration (VIV) vortex shedding mode, and the number of vortices released per cycle is much greater (at most twelve).