FOXM1 signalling pathways are highly expressed in multiple human cancers. Based on the crystal structure of the FOXM1 DNA binding domain, our preliminary research found ethylene glycol (4-benzyloxyphenyl) cyclopentylaminoethyl ether XST20, which could inhibit ovarian cancer cell proliferation and showed a medium affinity for the truncated protein FOXM1. This study intended to develop a FOXM1 inhibitor with stronger affinity and higher efficiency to be utilized as a molecular tool and drug candidate. We evaluated the optimization direction through molecular docking and systematically modified the structure of XST20. A novel class of ethylene glycol phenyl aminoethyl ether derivatives were synthesized, their anticancer activity and mechanism were evaluated, and the structure-activity relationship was summarized. Compound S2 showed a stronger affinity for FOXM1 and improved its activity with a broad-spectrum anticancer effect. S2 displayed selective antiproliferative activity against cancer cells with high expression levels of FOXM1 proteins. S2 should be a good chemobiological tool and a potential leading compound for future studies of anticancer drugs targeting FOXM1.