In order to investigate the effects of end anchorage method and prestressing level on the flexural behavior of reinforced concrete (RC) beams strengthened with carbon fiber reinforced polymer (CFRP) plates, an experiment was carried out on six large-scale T-beams. The failure mode, load-deflection curve, characteristic load, CFRP strain, CFRP utilization rate and ductility were analyzed. The results indicate that the anchorage method has a significant effect on the ultimate load of RC beams, whereas it has little effect on the cracking and yielding loads. With an increase of prestressing level from 0 to 0.5, the failure mode changes from the concrete crushing to the CFRP fracture and the cracking and yielding loads are increased by 75.0%-237.5% and 13.6%-50.9%, respectively, compared with the unstrengthened specimen. The ultimate load increases gradually in the concrete crushing mode but is affected limitedly in the CFRP fracture mode with an increase of prestressing level. The use of a reliable end anchorage can increase the CFRP utilization rate in the ultimate load; however, applying the prestress can considerably increase the CFRP utilization rate in the whole loading state.