Compaction of subbase is often the main load-bearing layer of a pavement. It is designed to evenly spread the load of the paving, it compacted with heavy equipment until the material forms a dense layer of interlocking aggregate. To perform well, subbase aggregates must be strong and durable, and must meet very specific graduation requirements. The main aim of this study is finding the effect of changing energy of compaction on the subbase. the sample of subbase is under class B after testing it by sieve analyses test, the physical properties as (specific gravity, elastic limit, plastic limit &max dry density) have been tested, the sample tested under different energy of compaction (modified proctor test and standard proctor test ) and found the effect of energy on (dry density, void ratio, porosity).