The invention relates to a liquid-solid slag discharging coupling boiler system suitable for combusting strong-slag-bonding and dirt-adhering solid fuel. The liquid-solid slag discharging coupling boiler system comprises a large-volume solid-state slag discharging boiler and a cyclone combustion boiler, and is characterized in that when the large-volume solid-state slag discharging boiler runs atthe load lower than 50%, the cyclone combustion boiler stops running; and when the large-volume solid-state slag discharging boiler runs at the load higher than 50%, the cyclone combustion boiler is selected to run according to needs. Through the reasonable design of the smoke side and the working medium side, the influences of a coupling system on an original large-volume solid-state slag discharging boiler system are greatly weakened, and the flexibility of the coupling system is sufficiently guaranteed.