Reactive Powder Concrete (RPC) is a new kind of engineering material with high strength, high elastic modulus and high durability. In order to satisfy the low-height requirement, RPC is adopted to design the railway bridge. One simple-supported RPC T-beam with span of 32m is designed and applied in railway bridge engineering. The height of the beam is 1.8m and the height to span ratio is 1/17.8. It is supper low-height beam for railway bridges. The parameters of material properties, mixing proportion, section size and prestressed steel strand cable arrangement of the RPC T-beam are presented. The load bearing capacity, the deflection and the crack resistance safety coefficient are calculated and the results can satisfy the requirements of the code. It is useful for the design and application of RPC in structure engineering.