Objective To construct an expression vector containing esp1 in order to investigate the effects on the chromatid separation. Methods A conditional plasmid vector containing esp1 was constructed, and was transfected into spc cells. The expression level of esp1 was detected by fluorescence microscopy, and the chromosomes were observed. Results EGFP-N1-esp1 was expressed in spc cells, and improper chromosome segregation was reduced. The plasmid of pTRE-d2EGFP-esp1 was constructed successfully. Conclusion Up-regulation of esp1 has inhibitory effects on the abnormal chromatid separation of tumors and may be potential in the treatment of cancer.