Noncovalent interactions,such as Hydrogen bonds and Halogen bonds are of critical importance in supramolecular chemistry,molecular biology,and materials science.Recently,similar bonding mechanisms have been proposed for adjacent main-group elements such as N,P and As,and noncovalent "pnictogen bonds" have been identified in crystal structures.Compared to Hydrogen and Halogen bonds,the angle of pnicogen bonds usually range from 160o to 180o,instead of 180o,mainly determined by the substituent group contacted to P atom.Pnicogen bond,as well as halogen bonds are all more sensitive to angular distortion than hydrogen bonds.In this paper the potential energy surface(PES)of pnicogen bond was yield from Ab initio calculations at MP2 level.The PES of PH2F interact with Ne along the angle showed that the dominant component of this weak intermolecular interactions is not van der Waals(VDW)effects but the electrostatic interaction.Then we extended our proposed Polarizable Ellipsoidal force field(PEff)for halogen bonds to understand the potential energy surface of pnicogen bonds.The development of molecular mechanics metod for intermolecular interactions is the basis to compute of macromolecular substances like proteins and self assembly structures.