Abstract: Based on investigating the effect of the test condition parameters on maximum index densities determined by vibratory table method and surface vibrating compactor method respectively for rockfill materials, and by comparing the laboratory maximum index densities with the dry densities determined by the current vibrating roller testing method in field, the test condition parameters of these laboratory methods are suggested. In addition, it is confirmed that there is a semilogarithmic linear relation between the maximum particle size and laboratory maximum index density, and the maximum index density of the rockfill prototype can be predicted by extrapolating to the actual maximum particle size of the prototype. It is recommended that the degree of compaction be used to determine the construction compaction criteria of rockfill materials in field.