The space-time profile of impurities has been measured with a multichannel visible spectroscopic detect system and UV rotation-mirror system in the HT-6M tokamak. An ideal impurity transport code has been used to simulate impurities (carbon and oxygen) behaviour during the OH discharge. The profiles of impuritie s diffusion and convection coefficient, impurities ion densities in different io nized state, loss power density and effective charge number have been derived. T he impurity behaviour during low-hybrid current drive has also been analyzed, th e results show that the confinement of particles, impurities and energy has been improved, and emission power and effective charge number have been reduced.