Abstract: π-facial hydrogen bonds are of importance to molecular recognition and protein structure research. In order to understand their properties, the structure and electron distribution of the π-facial hydrogen bonds are computed by means of AM1 MO method. The geometric parameters obtained from AM1 structure optimization are well in accordance with experimental results and give evidence for the existence of HF dimmer in HF-benzene system. The variation of electron distribution shows that π-facial hydrogen bonds are similar to classic hydrogen bonds in the interaction of the donor-receptor of the proton.