To investigate polysaccharide structure from Lonicera japonica , and study its effects on behavior of pancreatic cells, a homogenous polysaccharide, LJ-02-1, was extracted and purified from flowers of L. japonica by DEAE-cellulose and Sephacryl S-200HR column. The molecular weight was estimated to be 54 kDa. Monosaccharide composition was determined to be rhamnose, galacturonic acid, galactose and arabinose in the molar ratio of 10.77:7.88:15.45:65.89 by analyzing the PMP derivatives of the monosaccharides from 2 M trifluoracetic acid hydrolysis via HPLC. Based on methylation analysis, partial acid hydrolysis, and NMR spectra, the polysaccharide was elucidated to be a rhamnogalacturonan backbone and substituted partly at C-4 of rhamnose. The branches were determined to be T- and 1,4,6-linked β- d -Gal p , T- and 1,5-linked α- l -Ara f . The polysaccharide might inhibit BxPC-3 and PANC-1 pancreatic cancer cells growth at the concentration of 1 mg/mL with inhibitory ratio of 66.7% and 52.1%, respectively. [ABSTRACT FROM AUTHOR]