The Rayleigh-Taylor instability is a fundamental fluid instability of significant importance in various fields of physics, such as supernova explosions and nuclear fusion. It has been shown recently that an interface in a dusty plasma can be realized experimentally under microgravity conditions. This indicates that the Rayleigh-Taylor instability may occur at the interface of a dusty plasma. This study employs fluid dynamics models to theoretically analyze the Rayleigh-Taylor instability in dusty plasmas. The results show that the Rayleigh-Taylor instability in dusty plasmas not only depends on the number density of dust particles but also on the mass of individual dust particles. This result is different from previous studies, which show that the Rayleigh-Taylor instability depends on the mass density difference of the two fluids at the interface. By adjusting either the mass or the number density of dust particles in a dusty plasma, we can control the Rayleigh-Taylor instability in a dusty plasma.