The cylindrical Floating Drilling Production Storage and Offloading System (FDPSO) applied in the South China Sea is taken as an example to study the change rule of FDPSO heave and pitch amplitude under different damping plate cone angles. The wave loads on FDPSO are calculated by three-dimensional potential flow theory, the viscous damping is acquired through different methods, and the response transfer function of FDPSO is calculated. The spectrum analysis method is used to forecast the heave and pitch response, and the pitch response caused by second order wave loads is calculated. The results show that: the heave movement of the cylindrical FDPSO is intense, but the anti-shake performance is good; the increase of the damping plate cone angle is not conducive to the control of FDPSO heave and pitch responses, and the second order wave loads are of huge influence on the pitch response of the cylindrical FDPSO, which should be paid attention to.