Biogas purification is an effort to increase the calorific value of biogas. The CO₂ content in biogas causes the calorific value of the biogas to decrease, so it is necessary purification to increase gas levels CH₄. The research objectives were: To determine the effect of refining time on quality biogas, knowing the effect of gas flow rate on the quality of the biogas produced, and determine the duration of purification and the best gas flow rate for purification biogas. The research method used a completely randomized design (CRD) with two factors namely the purification time (15,20 and 25 minutes) and the gas flow rate (2,4 and 6 L/min) respectively repeated three times, then analyzed using the ANOVA test and followed by the DMRT test. The results showed that there is a significant effect on methane content, while carbon dioxide content has no effect real. The best purification time and biogas flow rate were 25 minutes (178,018.01 ppm) and 6 L/minute (474,744.3 ppm) because it produces the highest methane content, while for the content carbon dioxide at a purification time of 20 minutes (1201.62 ppm) and gas flow rate of 4 L/minute (52,012.4 ppm) produces the lowest levels of carbon dioxide.