Objective: To evaluate the influence of different pretreatment methods of post space on the removal effect for the smear layer on the dentin surface in the root canal and the bond strength of glass fiber post. Methods:Forty-four mandibular premolars were randomly divided into four groups according to the pretreatment method of post space after the same standard of root canal therapy and post space preparation. Group A was irrigated with distilled water（blank control group）; group B was irrigated with MTAD solution; group C was treated by ultrasonic irrigation; group D was treated by PIPS-Er:YAG laser. One sample was randomly selected from each group to observe the removal effect for the smear layer using a scanning electron microscope. The remaining samples from each group were glued to glass fiber posts using the RelyXTMUnicem self-adhesive cement

and the bond strength was assessed using the thin-slice push-out test; the bond strengths of coronal third

middle third

and apical third were calculated. A two-way analysis of variance and the Tukey test were performed to analyze the experimental data. Results:Compared with the control group

various pretreatment methods of post space could effectively remove the smear layer and improve the bond strength of glass fiber post

among which the PIPS-Er:YAG laser pretreatment had the best effects in both regards. Conclusion: The various pretreatment methods of post space in this study can effectively improve the bond strength of glass fiber post

among which the PIPS-Er:YAG laser technique has the best effect.