The influencing factors on the coarse grained soil dry density in the compaction test were fully analyzed and summarized in this paper from multi-perspective views.The three aspects of physical attribute

external factors and test operation were considered based on the system engineering method

which is termed as Wu-Li Shi-Li Ren-Li（WSR）.The index system of the influencing factors on coarse grained soil dry density in the compaction test was established based on WSR.The interpretative structure model（ISM）of the influencing factors on the coarse grained soil dry density was presented using interpretative structure modeling technique.The eleven factors in the WSR model were divided into five levels according to the influencing degree. The results were compared with practical experience.The results show that the accuracy of the test instrument

vibration force

surface pressure and vibration time can directly influence the coarse grained soil dry density in the compaction test and the results are similar with that of practical experience.