The objective of this study was to investigate and evaluate the biomethane potential (BMP) of Bougainvillea spectabilis Willd (BSW) waste in Yunnan, China, when subjected to mesophilic anaerobic digestion (AD). Three different categories of plant waste investigated were as follows: the flowers, leaves, and stems. These three portions were assessed for their BMP in a laboratory-scale batch anaerobic digester for a period of 60 days at 30 +/- 0.1 degrees C temperature. The results showed that the maximum daily methane yield of B. spectabilia's flowers, leaves, and stems were 65.95, 56.29, and 18.8 mL/(g square VS), respectively. The Gompertz equation presented the best agreement in the fitting progress.