In this paper, the capacity of outer oil film of floating-ring bearing was analyzed because the capacity of inner oil film is larger than the outer"s. Based on the DyRoBes software and Finite difference method, this paper analyzed the pressure of outer oil film by using the two ways and compared the two results. Because the structure characteristics of floating-ring bearing , the relationship of stiffness and damping of inner and outer films equivalent of the series of spring and damping, this paper calculated the total stiffness and damping of oil film of floating-ring bearing under different speeds. Using the method Routh-Hurwitz criterion analyzed the stability of oil film