Given the complex flight mission and structural characteristics of special-shaped tanks in new-generation space vehicles, this study investigates the sloshing characteristics and suppression methods of liquid propellant. Initially, the numerical calculation and structural suppression approaches for liquid propellant periodic sloshing are introduced. Subsequently, a new equivalent dynamic analysis approach based on the Volume of Fluid (VOF) method is presented and validated to simulate liquid sloshing and determine dynamic characteristic parameters such as sloshing mass, frequency, and damping ratio. Furthermore, anti-sloshing baffles are designed for sloshing suppression, and the influence of baffle height on sloshing frequency and damping ratio is examined. These significant findings provide crucial references and foundations for enhancing the flight stability and reliability of the attitude control system in new-generation space vehicles.