disclosed are 5 - nitrobenzoate derivatives of formula i , and the preparation method therefor , wherein r is referred to hydrogen , unsubstituted , mono - substituted , di - substituted or tri - substituted benzoyl moiety . 5 - nitrobenzoare derivatives of formula i do not affect the platelet aggregation , possesses the inhibitory activity related to the tumor cell - induced platelet aggregation , and further specifically inhibits podoplanin - induced platelet aggregation . therefore , 5 - nitrobenzoates of the invention are applicable in its therapeutic use as the novel therapeutic agent in preventing tumor metastasis .