Abstract: Abstract: Objective To observe the apical microleakage with simplified rotary ProTaper preparation method and to evaluate the sealing ability of the root apex. Methods Sixty extracted human teeth were randomly divided into two groups. In the experimental group, the root canals of 30 teeth were prepared with simplified rotary ProTaper method and obturated by 0.06 taper gutta percha cones with vertical condensation technique. In the control group, the root canals of 30 teeth were prepared with 0.02 taper stainless steel files in step-back technique and obturated by 0.02 taper gutta percha cones with cold lateral condensation technique. All specimens were penetrated by the line dye and the distances of dye penetration in the roots apical linear extent were measured. Results In the experimental group, the average value of the apical linear extent of dye penetration was 0.60mm with the standard deviation of 0.29 mm. In the control group, the average value of the apical linear extent of dye penetration was 1.18 mm with the standard deviation of 0.83mm. There was significant difference in apical microleakage between two groups (p<0.05). Conclusions The apical sealing effects of roots filled with simplified rotary ProTaper preparation method is better.