In order to explore the energy reuse potential of garden waste, Bauhinia blakeana Dunn branche and Zoysia tenuifolia waste were selected as raw materials, and they were pretreated with liquid hot water to obtain the process optimization results and improve the enzymatic digestibility. The results indicated that the optimal P-factor of Bauhinia blakeana Dunn branche and Zoysia tenuifolia waste was 1233 and 153 respectively. At this time, the Bauhinia blakeana Dunn branche and Zoysia tenuifolia waste got their total xylose yield of 85.48% and 68.40%, total sugar recovery of 87.84% and 86.31%. In addition, 72 h enzymatic digestibility increased from 43.99% and 55.94% to 81.25% and 87.27% after pretreatment, and Zoysia tenuifolia waste had better performance on enzymatic hydrolysis than Bauhinia blakeana Dunn branche. Liquid hot water pretreatment removed a large number of hemicellulose and some lignin, and there were significant changes in surface structure after pretreatment, it also increased the specific surface area and cellulose crystallinity index. All of these changes could help to improve the accessibility of cellulose to enzyme.Furthermore, a modified liquid hot water (MLHW) process was proposed to improve delignification of Roystonea regia leaves (LR) and leaf sheaths (LSR). As a less recalcitrant biomass with higher porosity (34.8%) and thinner cell walls (5.2 μm), LSR showed higher lignin removal (53.6%) than that (44.6%) observed with LR.