Abstract: The oil refinery effluent was dealt with biochemical treatment taking A²/O as a core, and its quality could reach the comprehensive discharge standard of effluent. The effluent could be recycled by the low pressure multi-effect evaporation system using the low temperature heat of oil refinery, and it was the new measure of energy saving and emission reduction. The silicon and turbidity were the main parameters of evaporation process. The removal effect of silicon and turbidity by softening with lime, magnesium salt precipitation and precipitation by combination coagulant of molysite and aluminium salt were researched. The results indicated that:when the dosage of Ca(OH)₂ was 500 mg/L, the removal rate of silicon and turbidity were 79.2% and 4.2%, respectively, and when the dosage of MgCl₂ was 400 mg/L at the pH value of 10, the removal rate of silicon and turbidity were 91.6% and 74.4%, respectively. The requirement of low temperature multi-effect evaporation system could be achieved, when the dosage of Fe(Ⅱ/Ⅲ)Al combination coagulant was 400 mg/L and the removal rate of silicon and turbidity were 91.9% and 90.4%, respectively. The residual silicon content and turbidity were 17.93 mg/L and 3 NTU.