The invention discloses a miniaturized oil field steam injection boiler. The miniaturized oil field steam injection boiler comprises a radiation section, a transition section and a convection section,wherein the radiation section is arranged at the right end of the transition section, the convection section is arranged at the upper end of the transition section; the transition section is formed by extending and coating a membrane type water-cooled wall of the radiation section, and the length of the transition section in the axis direction of a combustor enables the convection section and theradiation section to share a part of the light casting insulation layer. According to the miniaturized oil field steam injection boiler, the radiation section adopts the membrane type water cooling wall, so that the angle coefficient of the radiation heating surface is improved, and the heat absorption of the radiation section is increased; the water cooling wall is additionally arranged on the transition section where only the heat preservation material is laid, the area of the transition section is fully utilized, the temperature of the flue gas at the inlet of the convection section is reduced, and the high-temperature damage probability of the convection section pipe is reduced; and the length of the transition section in the axis direction of the combustor is shortened, so that the convection section is partially attached to the radiation section, the axis of the pipe in the convection section is parallel to the axis direction of the combustor, so that the axial size of the boiler is effectively reduced.