The invention discloses a pneumatic steady flame center staged combustor. A main combustion stage annular direct-injection type nozzle consists of a first oil inlet, a second oil inlet, an oil collecting cavity and an injection hole; a pre-combustion stage nozzle is provided with two independent gas collecting chambers and two rows of spray orifices which respectively spray nitrogen and methane/air premixed gas; and after entering an inlet of an annular combustion chamber, air is distributed into different flows which respectively enter a main combustion stage annular flow path and a pre-combustion stage pre-mixing channel. The main combustion stage direct-injection type nozzle transversely sprays liquid fuel oil into the main combustion stage annular flow path, and then the liquid fuel oil is mixed with main combustion stage air flow. The methane/air premixed gas and the nitrogen are obliquely and upwards sprayed into a backward-facing step pre-combustion stage by pre-combustion stage air flow; an electric spark igniter is positioned on a methane/air premixed gas injection track, and ignition starting of the pre-combustion stage is realized; and then high-temperature fuel gas of the pre-combustion stage ignites a main combustion stage. Mechanical components of the pneumatic steady flame center staged combustor are simple, stable and reliable in structure, and the liquid fuel oil can be efficiently and stably combusted in a wider incoming flow working condition range.