Benzofurans compound 2-(3',4'-dihydroxyphenyl)-3-methoxy carbonyl-5-methoxy carbonyl vinyl-7-hydroxy-2,3-dihydrobenzofuran (1) and benzodioxanes compound 2-(3',4'- dihydroxyphenyl)-3-methoxy carbonyl-6-methoxy carbonyl vinyl-2,3-dihydro-1,4-benzodioxane (2) were synthesized from caffeic acid through esterification and biomimetic oxidative coupling reactions. Moreover, a series of benzofuranneolignan compounds 3~7 and benzodioxaneneolignan compounds 8~10 were synthesized from compounds 1 and 2 respectively through acetylation, DDQ oxydehydrogenation, Pd/C catalytic hydrogenation, lithium aluminium hydride reduction and deacetylation in alkaline condition. All of these synthesized compounds were confirmed with MS, IR, 1H NMR and 13 C NMR spectra. Among them, 5~7,9 and 10 are new compounds. 8 is the natural product isoamericanol A. The biological activities of benzofuranneolignan compounds 1, 3~5 against five human cancer cell lines were evaluated in the standard MTT method, and the results have shown that compounds1, 3, 4 and 5 exhibit good inhibitory effect on leukemia cells (HL-60),lung carcinoma cell (A-549), breast cancer cell (MCF-7), colon cancer cell (SW-480), and hepatoma carcinoma cell (SMMC-7721).