The optimal conditions of remediation of sodium hyposulfite and the bioavailability changes of Cr in soil before and after remediation were studied. The results showed that for the chromium–contaminated soil, agent dosage was the factor that had the most effect on total and hexavalent Cr leaching concentration. The optimal conditions for the agent on the remediation of Cr–contaminated soil were 8% dosage, 0.5︰1 water soil ratio (v/w), 1 d curing time and 15 min stirring time. After remediation, bioavailability of the hexavalent Cr was significantly decreased by 63.21% – 84.67%, the carcinogenic risk of hexavalent Cr decreased 81.7%, and so the human health risk could be reduced effectively.