To understand the DNA methylation features of bamboo during its flowering process,we employed the techniques of HPLC (high performance liquid chromatography) and MSAP (methylation-sensitive amplified polymorphism) to detect the DNA methylation level of Bambusa multiplex (Gramineae,Bambusoideae),in a continuous period from its non-flowering to flowering stage.The results showed that DNA methylation rate of B.multiplex changed dynamically at different times.Furthermore,DNA methylation rates of flowering plant were significantly lower than those of non-flowering plant and non-flowering clumps.Total DNA methylation rates of 9.00% and 12.42% were detected in flowering and non-flowering plant,respectively,with full-methylation of 5.06% and 7.53%.Meanwhile,66.83% MSAP sites were identical both in flowering and non-flowering plants and 33.17% sites varied.Among those 33.17% variable sites,22.28% were demethylation and 1.98% were methylation in flowering plants,and other 8.91% variable sites gave a variance tendency between flowering and non-flowering plants.Therefore,demethylation and methylation happened simultaneously in flowering plants,with a much higher demethylation rate than that of methylation,thus exhibited a low methylation rate in flowering plants.