Abstract: Sludge burning is considered to be a kind of sludge reduction and recycling technology which has good prospects for development，it is becoming the mainstream way of sludge disposal． Environmental risks of sludge which from dyeing wastewater treatment facilities and centralized sewage treatment plants are the medium ones，and the recommended disposal is burning． By analysis and filter to sampling methods of ash’s characteristics identification which is from coal-fired power plant blending sludge，ash is identified according to standards GB 5085. 1—GB 5085. 6． It is recognized that the ash from coal-fired boilers blended dyeing sewage sludge and sewage sludge does not have the characteristics of hazardous solid waste，and can be utilized as general solid waste． The characteristics of ash depends on the properties of blended sludge， so the characteristics identification of ash is required before comprehensive utilization．