The molecular dynamic simulations have been performed on microsystem of liquid Co between 1873K and 300K; The pair distributed function and the change of atomic group at different temperatures have been obtained by the EAM method; If the cooling rate is low, the crystal would be formed. If the cooling rate is very high, the amorphism would occur. It is obvious that the ordering degress of liquid Co is strengthened with the temperature decrease. The last result of simulation has been discussed by the pair analysis technique. The various bond pairs in liquid Co are the basic units when they solidify. The micro configuration in liquid can be described by the bond pairs. When the liquid Co forms crystal, the pairs 1421 and 1422 play an important role. The inclination of changes of 1551 and 1541 is in accordance with the liquid and amorphism.

Key words: CHEMICAL KINETICS, COBALT, SIMULATION, LIQUID METALS, MOLECULAR STRUCTURE