Objective To evaluate the therapeutic effects of one visit root canal therapy(RCT) and several visit RCT for cracked teeth.Methods Cracked teeth with pulposis or apical disease were randomized to receive one visit RCTor several visit RCT,their responses were compared.Results The long-term therapeutic effects of one visit RCT were batter than those of several visit RCT,but the differences were not significant.The concomitant symptoms were significantly less and treatment time was significantly shorter in one visit RCT group as compared with several visit RCT group.Conclusion One visit RCT is recommended for the RCT of cracked teeth.