Taking the municipal sludge as the remediation objects and aiming at studying the effects of electrokinetic remediation of heavy metals from municipal sludge，model tests were carried out with different reagents，which were sophorolipid, rhamnolipid，saponin and composite reagents of biosurfactants and citric acid. Current density and heavy metal concentration in discharge liquid and sludge were examined and analyzed in order to explore the mechanism of reagents from the perspective of microstructure. The results demonstrated that the migration of heavy metals was mainly in the sludge and the concentration of heavy metals was very low in the discharge liquid. Best treatment was achieved around anode area and then followed by the cathode region, while heavy metals were accumulated in middle region. By comparing the removal effect of four biosurfactants, the highest removal rates of Zn，Cu，Ni and Cd were sophorolipid（53.85%），rhamnolipid（44.26%），rhamnolipid（56.33%） and sophorolipid（34.43%），respectively in anode region. Citric acid promoted the migration of heavy metals significantly in middle region, so that the removal rate with composite reagents of biosurfactants and citric acid were increased by 0.90%~16.08%. Based on the test results，it is recommended to apply sophorolipid or composite reagents with citric acid for high concentration of Zn and Cd in sludge treatment. As for high concentration of Cu and Ni, rhamnolipid or composite reagents with citric acid is a better choice.