The invention discloses a boiler fly ash ignition carbon measuring device, which comprises a sample feeding component, an ignition component, a transmission component, a sample weighing component, a sample discharge component and a crucible supporting plate. Crucible holes are arranged on the crucible supporting plate; the center of the crucible supporting plate is fixed to the top end of a pull rod passing through a station platform; a synchronizing wheel is arranged on the pull rod disposed between the crucible supporting plate and the station platform; a transposition motor fixed under the station platform is connected with the synchronizing wheel via a synchronizing belt; a sample feeding station, an ignition station, a sample weighing station and a sample discharge station are sequentially arranged on the station platform; the sample feeding component, the ignition component and the sample discharge component are respectively positioned above the sample feeding station, the ignition station and the sample discharge station; and the sample weighing component is positioned below the sample weighing station. By installing an electric scale below the station platform, the carbon measuring device enables the length of a weighing rod to be shortened heavily, enables the anti-vibration capability of the weighing rod to be strengthened greatly, and then improves measurement accuracy. Additionally, the crucible supporting plate is a strip-shaped plate with two through holes capable of holding a crucible, has simple structure, small rotation inertia, and is favorable for controlling accuracy of rotation.