The industrial production of humic acid usually are coal humic acid. There are evidence that lignin was the source of humic substance. Lignocellulosic materials can be the source of humic acid, which is easy to get and can help with clean the agricultural waste. In this study, steam explosion treatment Acacia find the most suitable conditions for production of humic acid, the use of experimental design to explore the oxygen pressure, sodium hydroxide concentration and tetrasodium pyrophosphate concentration in the range of 0~5 bar with 0.05~0.15M and 0.05~0.15M. The results showed that with 5 bar oxygen, 0.15M NaOH, 0.15M Na4P2O7, have the highest production of humic acid 4.9945g.