This research was examined the extraction of arsenic and mercury ions simultaneously from natural-gas-wells produced water through hollow fiber supported liquid membrane was examined. Aliquat336, Bromo-PADAP, TOA, Cyanex923, Cyanex921 and Cyanex471 were used as carrier extractants. The carrier dissolve in kerosene as liquid membrane was supported by hollow fiber hydrophobic micro-porous. Thiourea, sodium hydroxide, Deionized water, sulphuric acid, and nitric acid solution were used as stripping solution. The transport system were studied as function of types and concentrations of carriers in kerosene solvent and stripping solution, concentration of sulphuric acid in feed solution, synergistic of mixed 2 extractants and the number of run. The results demonstrated that all of carriers have the percentage of mercury more than 94%. TOA was the best carrier for mercury extraction and Bromo-PADAP was the best carrier for arsenic extraction with 66% removal. Only mixed between 0.40 mol/l of Aliquat336 with 0.06 mol/l of Cyanex471 was the synergistic extraction. Furthermore, when sulphuric acid solution was added in feed, The percentage of arsenic and mercury removal was increased. It is found that the concentration of sulphuric acid in feed at 0.1 mol/l and the number of run equal to 3 is the optimal condition that can reduce arsenic and mercury residue lower that standard.