Abstract: Objective: To investigate the effect of CarrisolvIII combined with 0.5%NaClO on removing the smear layer. Methods: Fifty maxillary incisors were randomly divided into 5 groups. During the process of preparation, five different fluids were used to irrigate the root canal. The amount of smear layer and erosion on the surface of the root canal walls were examined with the scanning election microscope. Results: The cleaning of root canal walls using CarrisolvIII combined with 0.5%NaClO was better than the CarrisolvIII or 0.5%NaClO alone, respectively. Conclusion: CarrisolvIII combined with 0.50%NaClO has a synergistic effect on the removal of the smear layer.