Abstract: Poly(p-phenylene benzobisoxazole)(PBO) films were modified by 70 keV N⁺ at room temperature with doses(the implanted nitrogen ion numbers per square centimeter) ranging from 1×10¹⁵ N⁺/cm² to 5×10¹⁶ N⁺/cm².The surface structure,composition and morphology were characterized by Fourier Transform Infrared Spectrometer(FT-IR),Raman spectroscopy(Raman),X-ray Photoelectron Spectroscopy(XPS) and Atomic Force Microscope(AFM).Effect of N⁺ implanted doses on surface structures and properties of PBO films were investigated.Results showed that the breakage and crosslink of chemical bonds and carbonization in the near-surface were observed after N⁺ implanted.With the N⁺ implanted doses increasing,the surface roughness increased,the contact angle decreased from 93° to 60° and the wettability increased by 35%,the conductivity had an improvement of three orders magnitude compared to pure PBO film,which reached 5.7×10^-9 S/cm.