The characteristic of anaerobic semi-continuous co-digestion of pig manure (PM) with rice straw (RS) and water hyacinth (WH) were conducted by using 60L semi-continuous digester in triplicate for 60 days. Three stages of anaerobic digestion process were identified: start up, first stage of stabilization, second stage of stabilization. In this research, acetic, propionic and butyric acid were the major composition of total volatile fatty acids (TVFAs). TVFAs mainly cumulated in late of startup stage and the first stage of stabilization process. The accumulation of TVFAs lead to dropping pH in these stages with the lowest value at 6.0. The concentration of TVFAs was recorded at 100% RS are 28.3mmol/L. The highest biogas production rate was achieved in 100% of water hyacinth treatment (315.5 mL/gVS/day). The experimental results show that biogas production rate of PM co-digestion with water hyacinth (198.6 mL/gVS/day) was higher than that of rice straw (148.8 mL/gVS/day). The methane content of the biogas from co-digestion of PM with RS and WH, varied between 53.4 and 51.2%, which was higher than that of from 100% of RS and WH (47.1 and 48.2%). Co-digestion of pig manure with rice straw and water hyacinth can be potential solution to enhance biogas production.