Sewage sludge is the inevitable product of wastewater treatment plants, which if not disposed of properly is a source of serious pollution to the environment. So before applying sewage sludge to agricultural lands it should be stabilized using suitable and simple processes to minimize its environmental hazards. Apart from the conventional methods used for the disposal of sewage sludge (direct use in agriculture, incineration and landfill), thermal process that converts waste biomass into biochar has been considered recently. This process leads to reduction of solid waste and removal of pathogens and organic compounds from sewage which is one of the challenge of its application. Besides, adding bio-char to the soil could improve the quality and health of the soil and increase crop yield. In the current study the feasibility of sewage sludge conversion to biochar in 3 temperatures including 300, 400 and 500 0C was investigated. Furthermore, the production of liquid fertilizer from the sewage sludge was investigated. The characterization of biochar and liquid fertilizer were determined considering various parameters including heavy metal concentrations (Zn, Pb, Cd, Cr, Ni, Fe and Cu), bio-available concentrations of heavy metals, total N, available phosphorus, exchangeable potassium, soluble sodium concentration, electrical conductivity, as well as biochar productivity, moisture and ash contents and pH In the next stage the effect of adding biochar obtained from the pyrolysis at temperature of 300 0C as a soil modifier in comparison to sewage sludge at levels of 0, 1, 3 and 5% w/w on corn (Zea Mays L.) growth were investigated over a period of 2 months in the greenhouse of Department of Natural Resources, Isfahan University of Technology. Additionally, changes in the availability of heavy metals extracted by ammonium bicarbonate- diethylene triaminepentaacetic acid (AB-DTPA) in the sludge and biochar samples, as well as heavy metals uptake by plants were measured. Atomic absorption spectrometer model Perkin Elmer (AAnalyst700) was used for heavy metal measurement. According to the California Food and Agriculture Organization standard, concentration of heavy metals, except for the amount of lead in Biochar produced at 400 and 500 ° C and nickel in all samples were in accepted ranges. Concentrations of heavy metals in the organic liquid fertilizer sewage were less than the amount reported by US- Environmental Protection Agency. Results showed that with increasing pyrolysis temperature from 300 to 500 ° C, the pH, the amount of ash, heavy metals and sodium content of biochar samples increased. In the other hand, biochar yield, the amount of total nitrogen, phosphorus, electrical conductivity, moisture content and the amount of available potassium decreased. Despite the increase in the concentration of heavy metals with increasing the pyrolysis temperature, metal concentrations extracted by DTPA, showed reducing the bioavailability of heavy metals including Zn, Pb, Cd, Cr, Ni, Fe and Cu, Total nitrogen, soluble potassium and heavy metal contents in organic liquid fertilizers decreased with increasing the extraction process, while, the amount of phosphorus, sodium, pH and electrical conductivity increased. Application of biochar enhanced wet and dry weight of shoots and roots, plant height, stem diameter, chlorophyll content and leave number of maize compared to the sludge treatment and control (soil without adding biochar and bio-sludge). The concentrations of Zn, Fe, Ni and Cd in shoot and root of maize cultivated in soil with biochar were less than the plants grown in soil with sewage sludge because of decreasing the bioavailable concentration of metals in biochar samples. Application of biochar and sewage sludge to soil generally improves biomass production of corn, but biochar was more effeive. The results showed that the biochar of sewage sludge could improve soil quality, enhance plant growth and reduce the risk of transfer of metals in food chain. Key words: Biochar, Environmental pollution, Heavy metals, Sewage sludge, Soil fertilit