Abstract: Using a heat conducting type automatic calorimeter made by Sichuan University as a basic element, we have constructed a new calorimetric vessel for the determination of heat effects of gas-solid interface reactions. The calorimeter was coupled with a set of gas-solid equilibration apparatus and heat constants of the system were caliberated by galvano-metric methods. The experimental equipments and manipulation procedures are described, and the accuracy of the measuring technique by peak height and envelopment area hase been found to within 0.5-1%. The system has been used for the determination of the relative partial molar enthalpies of the absorption of H₃ by LaNi₅, and the results are in good agreement with that cited in the literature^[2]. It is believed that this calorimetric system can be used for the investigation of heat effects of reaction between intermetallic compounds and hydrogen.