We evaluate the effects of soil in situ remediation by application of bone char as a soil amendment based on chemical and biological assessment. The application of bone char decreased the Pb in the in the water soluble (WS), exchangeable (EX), carbonate-bound (CAR) and Fe-Mn oxides-Bound (Fe-Mn) fraction but increased the Pb in organic-bound (ORG) fraction indicating the decreased bioavailability of Pb. The application of bone char decreased the Cd, Cu and Zn in water soluble, exchangeable, carbonate-bound fraction by increasing substantial amounts of heavy metals in the ORG fraction or Residual (RES) fraction. The soil genotoxicity was evaluated using plant comet assay of root tip cells of Allium cepa L. and the results indicated that bone char application reduced genotoxcity of heavy metals, decreasing the DNA damages in plants which was consistent with the changes of the chemical forms of Pb, Cd, Cu and Zn indicating the changes of the chemical forms of heavy metals may be one of the reasons for decreased soil genotoxicity.