The main objective of the present experimental investigation was to evaluate the performance of using a refitted anaerobic reactor system to treat the water hyacinth press juice. The biogas production rate was rapidly rising from 25 L.d-1 to 54 L.d-1 in the first few start-up days, there was approximately 1332 L biogas measured by wet gas meter and 62% of methane was detected during the experiment period. At the end of the anaerobic digestion treatment, it could be observed about 83.5% COD, 85.7% SS and 74.1% SS of the initial content was removed, declined from 7428 mg.L-1 to 1223 mg.L-1, from 6748 mg.L-1 to 967mg.L-1 and from 2315 mg.L-1 to 600mg.L-1, respectively. TN declined from 127.8mg.L-1 to 88.0mg.L-1 with a total loss of 31.2%. The variation of TP in the whole process was gradually declined, from 34.3mg.L-1 to 25.0mg.L-1, had total 27.1% lost. In the whole digestion process the pH increased slowly from 6.8 to 7.8. On the basis of the experimental results obtained, it is possible to conclude that: the refitted anaerobic reactor system for water hyacinth press juice digestion was practical and effective.