Abstract: Based on the Gaussian03 calculation software,the density functional theory UB3LYP and UB3P86,configuration interaction method UCCSD-FC and UQCISD-FC have been used to optimize the possible ground-state structures of PCl molecule,PCl+ and PCl- molecule ion with the 6-311++g(df,pd) basis sets respectively.Frequency and single-point energy scan for PClemn(n=-1,0,+1) have been calculated.Spectral parameters (Be,αe,ωe,ωeχe) of the PCl molecule and PCl+ ion ground state are obtained by least square fitting to the Murrell-Sorbie function.The results of calculation are in good agreement with experimental data.In this work,spectral parameters (Be,αe,ωe,ωeχe) of PCl- and force constants (f2,f3,f4) of PCln(n=-1,0,+1) molecule ion for ground state are shown for the first time.This calculation may provide important theoretical basis for investigation and further study of PCln(n=-1,0,+1).