Abstract: The cavitation flow is essentially compressible, so the compressible method is more appropriate for the physical essentials. The difference of gas and liquid in compressibility intensively deteriorates the stiffness issue in low speed cavitation flow simulation. A compressible solver is adopted to numerically investigate this kind of two-phase flow with precondition technique, to shrink the convergence course by dealing with the issue of imbalance of eigenvalues in low speed flow. Meanwhile, the dissipative term of Roe's scheme is rebuild on the basis of preconditioned system to improve the accuracy under low speed flow. Moreover, the phase transition and the material convection coexist in natural cavitation flow, and the fluids of gas and liquid vary much in density at normal temperature, these two factors are consequently followed by that the eigenvalues of source Jacobian matrix and inviscid flux Jacobian matrix differs in order of magnitude. This phenomenon is the "source stiffeness" problem and results in the unstability of the solver. The Point implicit method is applied to treat the source item, and the stability of method is enhanced by directly inversing the matrix. Three different operator splitting schemes are investigated in LU-SGS (Lower-Upper Symmetric-Gauss-Seidel) implicit iteration, and an operator splitting scheme suited for DDADI (Diagonally Dominant Alternating Direction Implicit) is developed. A comparison between the four implicit schemes is drew in NACA0015 hydrofoil low-speed cavitation case, to study the influence of different schemes on convergence. At the last part, the natural cavitation case of 3-D cone is simulated by the current method, capturing the main characteristic of the natural cavity flow field, and attaining a group of simulating data that matches well with the experiment data.