The work aims to study the feeding method and technical parameters in the measurement system of small granular hazardous chemical substance, with the feeding mode in the measurement system of the small granular hazardous chemical substance as the research object. Based on the physical and chemical characteristics of the material and the technical requirements for feeding safety, the gravity type feeding principle was used to study the feeding method suitable for hazardous chemical substance. By controlling the feeding door’s opening degree and the time length, the continuous variable-speed feeding was achieved, which could avoid the impact of the material and improve the measurement accuracy. The technological process suitable for the feeding of hazardous chemical substance is established and it provides certain technical reference for the safe measurement of hazardous chemical substance.