The invention relates to a sludge drying and burning technique and its system devices, applying to the handling of active sludge in urban sewage treatment plants, its process flows through: wet sludge stock house, measuring bin, sludge mixer, sludge dryer, granular splitter, cooler, drying products storage bin, incinerator, smoke gas cleaning devices, which is characterized by: said incinerator is bubbling fluid bed incinerator with coal economizer, air heater fixed in its end part, high-heat smoke gas generated by burning is used to heat heat-conducting oil and cool air individually, and heat-conducting oil after being heated is transferred to sludge dryer through the circulating pump to dry wet-sludge. The invention is characterized by: take heat-conducting oil as heating medium, use the heat generated by burning dry sludge to heat heat-conducting oil and then dry wet-sludge to make full use of resources; the volume-reducing quantity after drying and burning could reach over 90%; the percentage of desulphurization in incinerator could reach 75% as a result of adopting two stage technology of sulfur removal, and the gross percentage of desulphurization meets national environmental legislation requirements. The invention accomplishes the resources, volume reduction, and innocence of sludge.