Making lightweight ceramsite with sewage sludge is a new effective approach for disposal of sludge. However, there is a concern as to whether the heavy metals such as Cr 6+ in sewage sludge can be solidified in ceramsite after sintering. The configuration of Cr 6+ in ceramsite was analyzed by X-ray diffraction (XRD) and leaching tests were conducted to determine the effects of sintering temperature, pH and H 2 O 2 concentration on the stabilization of Cr 6+ in ceramsite. The results show that leaching of Cr 6+ changes little at temperatures above 900°C, and both pH and H 2 O 2 concentration have some effects on the leaching of Cr 6+ . Leaching test results indicate that Cr 6+ is stabilized in ceramsite and cannot be easily released to the environment again as secondary pollution, which eliminates the concern for its application. XRD analysis of ceramsite sintered at 1000°C reveals that the main compounds of Cr 6+ in ceramsite are Cr 2 O 3 and FeCrO 4 . The test results provides a better understanding of the factors that affect the mobility of Cr 6+ , and show it is a safe way to make ceramsite with sludge as an additive.