Effects of organic acids on Cd desorption from Cd-saturated soils and contaminated soils were studied. Results show: The desorption rate of Cd for three Cd-saturated soils and three contaminated soils could be characterized by valley-like curves with increase in tartrate or citrate concentration. Desorption rate of Cd was higher under the effect of citrate than under the effect of tartrate when concentration of the organic acids was higher than 2 mmol L^-1. Effects of tartrate and citrate on Cd desorption varied with the initial soil pH value. With increase in initial pH value from 2 to 8, Cd desorption rate for Cd-saturated soils and contaminated soils under citrate declined first, then rose, then declined again, forming a curve appearing like a lying "S". During the course a valley and a peak appeared clearly when the concentration of citrate was at 6 mmol L^-1. Under the effect of tartrate Cd desorption rate decreased with increase in initial pH value from 2 to 8. With higher electrolyte concentration, the desorption rate of Cd increased, moreover, Cd desorption rate with KCl electrolyte was higher than that with KNO₃ electrolyte under the same electrolyte concentration. What is more, effects of organic acids on Cd desorption remained more or less the same regardless of forms and concentrations of Cd in Cd-saturated soils and contaminated soils, initial pH value and type of electrolytes. From the results of this study, it could be concluded that avail ability of heavy metals was inhibited when concentration of organic acids was low. Contrarily enhanced availability would be found when higher concentrations of organic acids existed. So it is feasible to control the efficiency of bioremediation and phytoremediation for heavy metal contaminated soils by using different types of organic acids under varied conditions.