The invention provides a composition for inhibiting cancer metastasis, including: an effective amount of an amino acid hydroxamic acid derivative having a formula shown as formula (I), formula (II)or formula (III):a pharmaceutically acceptable carrier or salt, wherein the amino acid hydroxamic acid derivative has an effect for inhibiting cancer metastasis.本發明提供一種抑制癌症轉移的組合物,包括:一有效量之胺基酸羥肟酸衍生物,該胺基酸羥肟酸衍生物的分子式如式(I)、式(II)或式(III)或所示:;以及一藥學上可接受之載體或鹽類,其中該胺基酸羥肟酸衍生物具有一抑制癌症轉移的功效。