In terms of the environment problem caused by noxious gas HCl in medical wasteSpyrolysis progress, an absorption system using calcium-based absorbent was introduced based on combination reaction principle. An experimental equipment was developed in order to get HCl absorption efficiency using absorbent CaO. Under the constant gas volume rate and flow rate, the effect of the absorbent layer, CaO particle size, gasified gas temperature and water vapor content on dechlorination efficiency had been analyzed. The experimental result showed that the optimal absorption conditions of the absorbent layers were 3 layers, the particle size of CaO was 8 mm, and gasified gas temperature was 500℃ and the highest dechlorination efficiency was 98%. Within the experimental operating parameter range, high water vapor content favored the HCl absorption. The new dechlorination absorption equipment is suitable to absorb HCl efficiently in high-temperature simulation gasified gas and its structure is simple as well.