Abstract: The main influence factors on thermal decomposition of medical waste，such as sample type，heating rate，sample mass，end-temperature and heat-insulation time，were investigated by using TG-DTA. The experiment indicated that different samples showed different parameters of initial，final and peak temperature as well as weight loss rate，which represented the thermal decomposition characteristics of medical waste. The heating rate and sample mass apparently affected the initial and final temperature but contributed little to peak temperature and weight loss rate. While the end-temperature and heat-insulation time mostly contributed to weight loss rate，i.e.，the higher the end-temperature and the longer heat-insulation time，the larger the weight loss rate. However，their effects on initial and finial temperatures were negligible.