Abstarct: Nowadays studying and analyzing the relationship between different characteristics of various kinds of soil are very important. One of the most important parameter in soil mechanic is pre-consolidation pressure, the largest amount of pressure that the soil underwent previously. And also soil compaction is one of the most important processes in construction industry. The subject of our research is the analysis of the effect of compaction effort on the pre-consolidation pressure of clay soil. Our analyzed soil belonged to Sa’ad A’bad village in Shahroud periphery. At first compaction operation was carried out on the soil with 5 diverse energies. The best moisture (ωopt) and maximum dry density (ꙋdmax) for each of them had been achieved. Again the soils had been achieved in their optimal moisture and had been compacted with related energies. Two samples were made from each compact operation and they were put in consolidation machine for consolidation test. At last compression index, coefficient of volume change , coefficient of consolidation and pre-consolidation pressure parameters achieved through the tests, were analyzed. To get the stress of pre-consolidation through the test, two methods of Silva and Casagrande were used, of which the results were compared. It has been concluded that increasing the compaction effort will increase the pre-consolidation pressure with both methods, and the amount is in the form of nonlinear equation. And also the amounts of pressure shown by Silva method were less than those reached by Casagrande method.