The theoretical study of reaction between PH2 and NO on the ground state potential energy surface is reported by using molecular orbital ab initio calculation and density function theory (DFT). Equilibrium structural parameters, harmonic vibrational frequencies, total energies and zero point energies of all species during reaction are computed by HF, MP2 (full) and B3LYP theory levels with the medium basis set 6-31G*. Theoretical results indicate that intermediate IM1(H2PNO) is firstly formed by overcoming a small energy barrier TS1, and then two four-mem-bered ring transient states TS2 and TS5, with energy barriers 103.3 and 102.6 kJ/mol respectively, then H-migration and isomerization are completed and the products PN and H2O are formed. The reaction is exothermic one with -189.6 kJ/mol released. The theoretical study of reaction between PH2 and NO on the ground state potential energy surface is reported by using molecular orbital ab initio calculation and density function theory (DFT). Equilibrium structural parameters, harmonic vibrational frequencies, total energies and zero point energies of all species during reactions are computed by HF, MP2 (full) and B3LYP theory levels with the medium basis set 6-31G *. Theoretical results indicate that intermediate IM1 (H2PNO) is uniformly formed by over a small energy barrier TS1, and then two four- mem-bered ring transient states TS2 and TS5 with energy barriers 103.3 and 102.6 kJ / mol respectively, then H-migration and isomerization are completed and the products PN and H2O are formed. The reaction is exothermic one with -189.6 kJ / mol released .