Aiming at the fluid-structure interaction vibration of the valve core-stem system in a single-type control valve, a dynamic simulation model of this system was built with consideration of a valve positioner. The predictor-corrector method was given for solving response of the valve core-stem system. The vibration response of the systems was analyzed by ANSYS software under the conditions of fixed and varying opening as well as flow-opening and flow-closing. The research results show that, for fixed opening, the valve core steady displacement offset and the fluid imbalance force increase with the increase of the pressure difference and the decrease of the opening; the transient time of the valve core dynamic displacement is shortened with the increase of the pressure difference, and the valve core dynamic displacement response amplitude under flow-opening is greater than that under flow-closing. For reducing the opening, the transient time of the valve core dynamic displacement is shorter than that under flow-closing, and the greater the pressure difference, the shorter the time, while under flow-opening it is opposite; for increasing the opening, the relation between the transient time and the pressure difference is contrary to that under reducing the opening.