A vibration control strategy based on nonlinear targeted energy transfer (NTET) for suppressing galloping of the cylinder is proposed in this study. The effect of NTET on controlling galloping responses was explored from both theoretical and experimental aspects. The fluid force was described based on the quasi-steady theory. The dynamic theoretical model was constructed by using the energy method. The theoretical model was validated by comparing the predicted results with experiments. The linear dynamic analysis shows that increasing the spring pretension can increase the coupled damping ratio and frequency. As a result, the onset wind speed of galloping for the square cylinder is decreased. The nonlinear dynamics analysis reveals that the NTET's linear and nonlinear stiffness have an effect on the vibration responses. There is an optimal value of linear stiffness where the suppressing effect is the best. The larger the nonlinear stiffness is, the better the control effect of the NTET. What’s more, the smaller the spring pretension of the NTET, the larger the spring stiffness, and the lower the amplitude of the cylinder. This study can provide theoretical support and experimental data for effectively designing galloping control strategies in engineering applications.