This study aims to investigate the chemical constituents of the leaves of Cinnamomum cassia. The extract of the leaves of C. cassia was separated and purified utilizing chromatographic techniques including macroporous resin,ODS,silica gel column chromatography and semi-preparative high performance liquid phase.Eight compounds were isolated from the n-butanol fraction of the leaves of C. cassia,and their structures were identified as (7S,8S)-4,9,7′-trihydroxy-3,3′,5′-trimethoxy-8-O-4′-neolignan7-O-β-D-glucopyranoside (1),grasshopper ketone (2),citroside A (3),loliolide-β-D-glucopyranoside (4),methyl dihydromelilotoside (5),methyl 2-phenylpropanoate-2-O-β-D-apiofuranosyl-(1→6)-O-β-D-glucopyranoside (6),2,3-dihydroxy-1-(4-hydroxyl-3,5-dimethoxyphenyl)-1-propanone (7),4-O-(2-hydroxy-1-hydroxymethylethyl)-dihydroconiferyl alcohol (8).Among them,compound 1 is a new phenylpropanoid glucoside,and compounds 3-5,7,and 8 were isolated from the plant for the first time.Compounds 2,3,7 and 8 could significantly increase the glucose consumption in insulin-resistant HepG2 cells at a concentration of 10.0 mol/L.