Abstract: In order to study the sample preparation method and influence of cell pressure on mechanical properties of asphalt concrete specimens,two sample preparation methods conducted for asphalt concrete specimens and four group triaxial tests with different cell pressure analyzed respectively in this paper.It concludes that,the higher cell pressure results in higher failure strength of asphalt concrete,and also leads to lower sample dilatancy.Compared with indoor simulation drilling sample,the peak intensity of compaction shaping sample is higher in（σ₁-σ₃）-ε₁ curve,the initial tangent modulus is greater,the phenomenon of shear dilatancy is more obvious.Fitting the test curve with Duncan-Chang model,indicated that the fitting effect of Duncan-Chang model on the stress-strain of asphalt concrete is not well,and Duncan-Chang model can not be simulated accurately to reflect dilatancy and softening phenomenon of asphalt concrete as well.