The invention discloses a technology reducing carbon content of boiler fly ash. The technology comprises a first step of sieving fuel coal, differentiating fuel coal cast in a fuel coal sieve according to grain size by a classifier, a second step of controlling feeding, controlling feeding time of a first bunker, a second bunker and a third bunker via a control circuit, a third step of mixing fuel coal, evenly mixing feeding coal of the first bunker, the second bunker and the third bunker via a mixing machine, conveying the material evenly mixed to a boiler port, and a fourth step of controlling coal casting speed, controlling mixed material casting time to the port via the control circuit. The technology reducing carbon content of boiler fly ash can be applied to the technical field of boiler burning; a present burning boiler can be improved and a boiler combustion chamber can fully burn; and boiler fuel coal utilization rate can be improved and business economic values can be improved.