A series of 3-substituedmethylenethiochroman-4-ones was designed and synthesized,and their structures were confirmed by 1H NMR,13C NMR,MS,IR,UV and elemental analysis.The results of their anticancer activity studies show that almost all 3-chloromethylenethiochroman-4-ones exhibit high anticancer activities and their activities are all better than reference cisplatin.Their IC50 against cancer cells is in a range of 0.80-9.17 μg/mL.Thus they could be promising candidates for anticancer drugs.However,compound 5 has no activity against cancer cells,thus chloromethylene at the 3 position of thiochroman-4-ones seems to play an important role in observed anticancer activities.