Abstract: The changes of chemical composition and antioxidant capacity of garlic,onion and ginger were studied.The results showed that the water content of six forms of garlic,onion and ginger was decreased rapidly after thermal processing optimum parameters of previous optimized in 75 ℃,85% humidity constant temperature and humidity box for 8 days. Furthermore,reducing sugar,total sugar,total acid,protein and other nutritional components content were also increased,the polyphenol content had become larger,and the color became deep.The antioxidant capacity of threekinds of spicy vegetables was increased in different degrees after heat processing.Among the reduction ability,scavenging hydroxyl free radical ability,scavenging superoxide anion free radical ability and scavenging DPPH free radical ability,ginger had maximum increase with an increase of 2.5times,8.5 times,3.2 times,4.6 times,respectively.