The invention provides a steam boiler which comprises an upper boiler barrel, a lower boiler barrel, ascending pipes and descending pipes; the ascending pipes and the descending pipes are connected between the upper boiler barrel and the lower boiler barrel; flow stabilization devices are arranged in the ascending pipes; each flow stabilization device comprises a core body and a shell; the core bodies are arranged in the shells; the shells are connected with and fixed to the inner walls of the ascending pipes; each core body comprises a plurality of radial rods extending from the center of thecore body to the radial directions; a plurality of fins extending from the radial rod down are arranged on each radial rod; the fins are provided with sharp parts; and the sharp parts face downwards.With the adoption of the novel structure steam boiler with the flow stabilization devices, when gas-liquid two-phase flowing exists in the ascending pipes, heat transfer is improved, vibration of theascending pipes is weakened, and the level of noise is lowered.