A method of combining theoretical analysis with numerical simulation is presented to achieve real-time vibration control of steel strip immersed in fluid during continuous hot-dip galvanizing process. Theoretical and numerical methods are employed to investigate inherent properties of strip and immersed strip, respectively. Multivariate quadratic regression is adopted to fit the ratio of natural frequencies. Keeping inherent frequencies far from excitations is taken as optimization objective, based upon field testing results. Real-time vibration control of immersed strip near the air knife box is carried out by varying production parameters. The results reveal that width, thickness, tension and molten zinc have noticeable and highly nonlinear effect on inherent properties of steel strip. Axial speed of strip is negligible in calculations of natural frequencies. Wind load of air knife moving relative to strip is the principal source of vibration. The approach of combining theory with numerical computation can meet the requirement of real-time vibration control of alloy strip.