Abstract: In order to investigate the flexural capacity and deformation performance of prefabrication and assembly beam，three prefabrication and assembly beams and one cast-in-place RC beam were fabricated and the flexural capacity tests of RC beams were carried out． The mechanical properties of prefabrication and assembly beam with cast-in dapped-end connections were analyzed． The results showed that the failure mode and deformation of the prefabrication and assembly beam could meet the design requirements，cracking load and ultimate load were basically the same as the cast-in-place RC beam． Based on test data，the suitable range of the length of the precast section of the prefabrication and assembly beam was found out．