With the phosphors emission regulations in wastewater are getting more and more rigorous in China,the content of phosphors in sewage sludge(SS)is higher and higher.Considering the large amount,studying on the recovery of P in SS is very necessary.Our project aimed to recover the P in SS through a two-step thermo-chemical treatment: the sludge incineration completely destructs the organic pollutants,P and heavy metals as much as possible are enriched in the sewage sludge ash(SSA)in a first step.Calcination treatment of phosphorus-enriched SSA removes the heavy metal while ensuring a high fixed rate of P in a second.