The objective of this study was to determine content of polyphenolics and flavonoids, antioxidant activities, and inhibitory activities of lipid accumulation and CETP (cholesteryl ester transfer protein) in water extracts from Acanthopanax koreanum branch (AB), Morus alba leaf (ML) and brach (MB), and Camellia sinensis leaf (CL) parts. Total phenolics content at 2,000 ㎎/㎏ extract was highest in CL, (1,162.0 ㎎/㎏), and followed by AB (244.0 ㎎/㎏), ML (191.0 ㎎/㎏) and MB (165.9 ㎎/㎏) (lowest). Total flavonoid level had same tendency to total phenolics with significant differences, showing highest (46.9 ㎎/㎏) in CL and lowest (12.9 ㎎/㎏) in MB. DPPH (1,1-diphenyl-2-picryl hydrazyl radical) free radical scavenging activity of water extracts from all the plants concentration-dependently increased and showed highest activity in CL, followed by AB and lowest in MB. Lipid accumulation significantly decreased by 72% and 84% upon treatment with 100 ㎎/㎏ of CL and ML, respectively (p<0.01), showing highest lipid accumulation inhibitory activity in CL. CETP was inhibited by 19% and 15% upon treatment with 100μg/mL of CL and AB, respectively, Therefore, water extracts from Camellia sinensis leaf (CL) above 30 ㎎/㎏ significantly decreased lipid accumulation of 3T3-L1 cells, inhibited CETP, showing highest antiobesity activity.