The characteristics of anaerobic batch co-digestion of water hyacinth (WH) with pig manure (PM) under seven mixing ratio 100%WH; 80%WH : 20%PM; 60%WH : 40% PM; 50%WH : 50%PM; 40%WH : 60%PM; 20%WH : 80% PM and 100% PM  were investigated, each treatment was conducted in five replications with daily loading rate at 1 gVS.L^-1.day^-1. During the anaerobic digestion process (60 days), two periods were maximum biogas production, the first stage from 12 - 22 days and second stage from 30 - 35 days. The maximum daily biogas productions from each stage were 17.2 L.day^-1 and 15.1 L.day^-1. The cumulative biogas production varied between 60 L (100%PM) and 360 L (60%WH : 40%PM). The results showed that the biogas yields of co-digestion 40 - 80% WH were increased the production from 34.6 - 56.1% in comparison with 100% PM and 109 - 143% with 100% WH. Methane content of all treatments more stable when mixing with WH and with more methane than 45% (v/v) that good for energy using purposes.