The effects of growth stages on the physico-chemical properties and anaerobic digestion performance of Pennisetum hybrid were studied in batch mesophilic experiments. The results indicated that the content of C，TS, VS and lignin increase over time at different growth stages. The dry matter yield per hectare firstly increases then declines, with the highest dry matter of 15.01t/hm2. Biogas production performance of Pennisetum hybrid firstly increases and then deceases, and the maximum biogas yield is obtained when Pennisetum hybrid is harvested at 60d growth stage, which are 0.68L biogas/g VS and 0.37L methane/g VS. Based on the biomass yield per hectare and biogas production of Pennisetum hybrid, the area specific biogas yields of 848.07～6279.73m3/hm2 can be achieved from 〖JP2〗the Pennisetum hybrid harvested at different growth stage, the corresponding energy production of 165.49～〖JP〗292.66GJ per year. Biogas production from Pennisetum hybrid suggests that the energy grass is a potential material for anaerobic digestion.