Abstract: The structural and electronic properties of carbon nanotubes（CNTs）doped with nonmetallic element N，B，Si or F are discussed.Research& development efforts on fields including field emission，energy cells and gas sensing are presented for the doped CNTs.The doping could increase the defects in CNTs and alter the electronic structures.The CNTs could be transferred to N-type semiconductor or metallic conductor from the doping，leading the improvement of the field emission.The doping could also transfer CNTs to P-type semiconductors，caused the degradation of field emission.There is an optimized value of doping content with the improvement of field emission.The studies of the nonmetallic doping in CNTs are very important for various practical applications.