Optimum conditions for benzene synthesis and liquid scintillation counting have been studied for the determination of radiocarbon age. In benzene synthesis the carbon dioxide converted to benzene with high efficiency of 91%. Yields of each step with 10L of carbon dioxide were $CO_2$ $ ightarrow$$C_2H_2$(94%), $C_2H_2$$ ightarrow$$C_6H_6$(96%) and$CO_2$$ ightarrow$$C_6H_6$(91%), respectively. Benzene synthesized from oxalate was measured with purity of 95% by GC /MS. $delta^13$(C$^13$C/$^12$C) of oxalate was measured to $-24.7{textperthousand}$ by massspectrometer. For liquid scintillation counting of benzene sample low background and highest FOM were measured in 0.5 ml cocktail and 3 ml standard solution with the range of 15.4∼74.9 KeV window setting. Oxalate and background samples weremeasured to $28.7pm0.12$cpm and $3.92pm0.04$ cpm in 15.4∼74.9 KeV