Treatment of landfill leachate using ozonation and coagulation process were investigated. Ferric(III) chloride and Cation were found to be effective coagulants to treat landfill leachate. In the case of ozonation, leachate qualities were improved as pH increasing. Preozonation process removed more CODcr, Color(535nm) and Turbidity than Post-ozonation about 8%, 3.5% and 1% respectively.