The invention relates to a closed feeding method for solid material of reaction kettle. The problems solved by the closed feeding method for solid material of reaction kettle are the dangers of dust in current technologies, the difficulties in achieving a completely closed feeding method and the difficulties in cleaning. By adopting a closed feeding method for solid material of reaction kettle, a completely closed feeding method and a non-oxidation operation of material are fulfilled. The impacts of poisonous solid material with sensitization on the safety and the health of workers are addressed. Production safety and product quality are improved. With good technological effects, the closed feeding method for solid material of reaction kettle can be applied to the feeding of solid material in reaction kettle.