The self-modified quasi-stationary model for radiation ablation has been established in this paper based on physical picture of numerical simulations. The objective of the model is to predict quantitatively the scaling laws of various ablation parameters driven by soft-X-ray, such as the dependence of ablation depth, pressure on radiation temperature, energy, pulse width, without resorting to complex computer simulations. The computational results are given fot some interstng materials in ICF. Scaling laws obtained in this paper are simple and effective in target design and analysis of experimental results.