In order to investigate the flexural behavior of Reactive Powder Concrete（RPC） beam with externally prestressed Carbon Fiber Reinforced Polymer（CFRP） tendons，four beams specimens with different shear-span to depth ratios, tension control stress of the tendons and partial prestressing ratios（PPR） were tested. Based on the experimental results，the failure patterns of the beams were clarified, and the equations for predicting the cracking and ultimate moments of the beams were proposed and verified. The results show that the failure mode is similar to the under reinforced RC beams for all fully prestressed beams of PPR 1.0 without any internal steel reinforcements. Increasing the tension control stress of the tendons could enhance the cracking load of the fully prestressed beams，but could not change the failure mode. Compared with the fully prestressed beams, the ultimate capacity and ultimate deformation of the partially prestressed beam with steel reinforcements（PPR 0.7） increase by 88.7% and 18.1%, respectively. The ductile failure mode with the yielding of steel bars followed by the crush of RPC in compression zone was observed in the partially prestressed beam. The steel fibers in RPC have a limited effect on the flexural performance of the fully prestressed beams, while the steel reinforcements might improve the behavior of the beams significantly. Therefore，it is not suitable to overestimate the role of steel fibers and remove the use of non-prestressed reinforcements in the RPC beams.