By shearing tests of asphalt mixture,it was found that the shearing strength variability was increased with increasing maximum nominal size.When the maximum nominal size is larger than 16 mm,the strength variability of the tests becomes more dramatic.And in the research with different sample sizes it is also found that the strength variability is reduced with increasing press head size.Therefore,it was necessary to study the shearing test standards for different size of asphalt mixture.The test parameters,shearing stress coefficient for different nominal size were determined.Further more,the shearing test parameters for non standard sample were determined,the shearing stress coefficient and height calibration coefficient were also obtained.