Objective: To analyze the influence of temperature on the clinical efficacy of AH-Plus paste, so as to provide clinical evidence for a one-time root canal therapy to control the temperature. Methods: 48 teeth were numbered and randomly divided into 3 groups, with AH-Plus paste at different temperatures on isolated root canal filling, dye penetration method was used to detect micro leakage, observing of combination between wall and the root canal sealers with scanning electron microscope. Results: 1) In the coronal micro leakage, under different temperature on coronal micro leakage values were not significantly different (P>0.05); 2) for the apical micro leakage, group C was significantly less than that of group A and B (P<0.05), group A and B showed no significant difference of the apical micro leakage (P>0.05); 3) scanning electron microscopy of the apical zone found that in group A (150 DEG C) root canal between the wall and the gutta percha gap was significantly higher than that of group B and C. Conclusion: When using AH-Plus hot gutta percha vertical as the method to compact during root canal obturation, setting the gutta percha temperature may affect apical micro leakage. Higher temperature may produce less micro leakage than lower temperature group and no significant difference for the coronal micro leakage.