Abstract: Objective Study of different bonding methods and thermal cycle on breaking strength of Cerec allceramic crowns after bonding. Methods 80 in vitro premolars were selected for Cerec allceramic crown preparation and were randomly divided into 4 groups（n=20） according to their luting agent:Group 1:VariolinkN resin binder and silane coupling agent; Group 2:VariolinkN resin based luting material; Group 3:Bisco Choice TM2 resin adhesive and silane coupling agent; Group 4:Bisco ChoiceTM 2 resin adhesive.Each group was divided into A(without thermal cycling) and B(with thermal cycling) subgroups.The maximum breaking strength of the allceramic crowns was tested by the universal mechanical testing machine,the bond failure forms were recorded,and statistical analysis was done thereafter. Results Group 1,using the Variolink N resin based luting material and silane coupling agent,got the highest fracture strength of Cerec allceramic crowns among all the luting agents.Non thermal cycling subgroup was higher than that of thermal cycling subgroup in flexural strength of allceramic crowns.The difference was statistically significant (P<0.05). Conclusions The dualcured resin based luting cement system is the ideal choice for dental feldspathic ceramic bonding,and can get a higher breaking strength.The breaking strength of Cerec allceramic crowns can be reduced by thermal cycling.