Abstract: According to the similarity and the monotonic characteristics of the compaction curves between the compacted and the decompacted states,the paleo-porosity-depth function φ'(Z) and the paleo-density-depth function ρ'(Z) was supposed.By using the principle which formation grain volume and mass have been keeping constant,the compaction correction equations has been established. Further,the decompacted thickness S and the average paleo-density ρ_s can be calculated and the grain density of the compacted and decompacted states can be kept constant.