Abstract: The similarity and difference between the bond orientational order and pair analysis methods have been first identified with the help of molecular dynamics simulation and the steepest descent minimization of potentials techniques. The binary liquid K-Rb alloys are chosen as an example.Results show that the bond orientational order parameters may be a relevant direct measurement on the perfection of an icosahedron. The PA formula (1551 bonded pairs) is, however, responsible for the total number of various icosahedra. In addition, it is found that pair analysis approach is more sensible to local structure than that for bond orientational order.